If we want to feel comfortable about ourselves and develop a feeling of substance, we need to be clear about what we think, and about what we feel. One way to do that is to avoid lying to ourselves.
  Most of us lie to ourselves because it’s convenient. A person generous with their money might, for example, conclude they are kind. It’s an easy and convenient assumption to make. It may even be right. But there are other possibilities: perhaps the person feels unworthy of having money. Or, they might feel responsible for other people’s problems, and feel anxious, and being generous would help relieve their anxiety. Or, they might be unable to refuse a request, fearful of being perceived as selfish.

‘If you find that you drink an unhealthy amount, you might tell yourself that you are choosing to relax and unwind with a few drinks after work and you just got caught up in the moment, but maybe the real choice you have made is to deny your alcoholic tendencies or to shorten your life expectancy.’
Domonique Bertolucci, in his book, ‘The Happiness Code’.

When we are at the mercy of motives we don’t fully understand, we can’t truly know who we are, and we can’t always make the right decisions. We might drift through life buffeted by our misconceptions, only dimly aware of what is going on. However, when we face the truth head on, it slowly becomes easier to see, and easier to accept. We then lose our fear of it, and begin to make sharper decisions.
  If the generous person were to know their true motives it doesn’t mean they will be less generous, or less helpful, but it does mean they will be aware of the forces driving them. That’s important. It’s important for all of us if we want life to run smoothly.

‘I think it bodes well for us to deal with difficult situations in truthful ways, facing discomfort, so that we build on forging a stronger, more secure voice.’
Anonymous, found in Gerald Dworkin’s article, How You Justified 10 Lies (Or didn’t).

Some of us tend to take the credit for things that go well, and find excuses when things don’t. Some of us fool ourselves into believing in New-Age guff like astrology, and psychic powers. Some of us even believe we have those powers! And, some of us believe in anti-ageing creams, weight loss pills, and internet scams.    
  We believe because we want to. We choose to not see the truth.

‘When we don’t want to see the truth we’ll lie to ourselves. These lies are the toughest to spot because they are our own. . . . Only the exceptional person is willing to look at what he doesn’t want to see, listen to what he doesn’t want to hear, and believe that which he wishes would not exist.’
David J. Lieberman, in his book, ‘Never Be Lied to Again.’

So, how can we avoid lying to ourselves? Simple: by not lying about ourselves. When we lie to someone about ourselves we also lie to ourselves. If we feel the need to hide the truth from someone it means we ourselves are not fully accepting the truth.

‘By lying to people I’ve been putting myself down too, just by sending a message to myself that I’m not good enough.’
Unknown.

We need to face the truth head-on, not hide from it. That can be enormously uncomfortable. Yet that truth will slowly become easier to accept. Then we lose our fear of it. And when we spend less energy hiding the truth from ourselves and from others, we can relax and go easy on ourselves. And feel less anxiety.
  There are exceptions. Disclosing too much of ourselves can at times be off-putting for others. We need to be sensitive to the other person’s interest, and choose carefully.
  Also, being too revealing might leave us open to persecution.
  Allow yourself to be vulnerable in the company of people you trust. Or always ensure that if your trust were betrayed, you could handle the consequences. What are the worst consequences possible? Could you handle them?
  If you want to refrain from disclosing information about yourself, fine. You were not put on this planet to answer people’s questions. Say, ‘I decline to answer.’

How to avoid lying about yourself:
1. Be honest about what you are feeling.
If you pretend to feel one emotion while feeling another, pretty soon you won’t know what you are feeling. We need a clear understanding of our emotions to avoid being led by them, and to get that understanding we need to know them. Lying to other people about our emotions will distort that process.     ‘Hey guys, I’m actually frightened.’
      ‘I am feeling irritated right now.’
A further benefit: you will connect with people on a deeper level. They know where they stand with you and feel comfortable being with you.

2. Be honest about what you are thinking.
If you don’t want people to know what you are thinking, decline to tell them. Don’t lie about it. But when you do disclose your thoughts, tell the truth.
‘Hey, I don’t understand.’
‘I do think . . . and here is why.’
‘I disagree, but prefer to not explain why.’ (That’s better than fibbing.)

3. Be honest about your achievements or your abilities.
Don’t exaggerate them, and don’t undermine them.
  If you exaggerate your achievements you are pretending to be a person you are not, and that will prompt a voice in your head to sneer, ‘phoney!’ You don’t want that. You might impress others with your exaggerations, but you’ll just feel like an imposter. And feel anxious wondering if you will be found out.
  Don’t undermine your achievements or abilities either. That’s not humility, that’s lying.

4. Be honest about your mistakes.
Having the ability to admit faults and mistakes is an attractive quality, as is the ability to laugh at oneself and not take oneself too seriously.

In summary, being truthful with others, about what you think and about what you feel, will help you be aware of what you really do think and really do feel. That understanding will ground you. Instead of becoming a composite of lies and mixed messages, you will become consistent, stable, and self-knowing.
  To lie about yourself can conceal a wound and let it fester. To tell the truth about yourself can open that wound and let the pus drain. It’s uncomfortable initially, but it heals.
  When you speak the truth about yourself you discover that truth, and discover yourself.

 ‘. . . keeping secrets reinforces the perception that their shame is justified, and that catastrophic consequences would follow should others find out. This maintains their anxiety and perception of defectiveness. One of the best ways to evaluate whether our beliefs are correct is to conduct a behavioural experiment . . . self-disclose to the relevant people and observe their responses. Once we ‘come out’, our anxiety drops because we no longer need to worry that people will find out. In addition, in most cases people do not react with the harsh judgment that we had predicted, and so we get immediate evidence that our perceived failings are not so bad after all.
   But what if they do? Behavioural experiments with self-disclosure always involve some risk . . . sometimes our fears are realised . . . However, we do not overcome our self-doubts and fears without taking risks . . . The most powerful learning occurs when we risk the possibility of disapproval and discover that in most cases it does not happen, and that even if it should happen, that we can cope.’
From Sarah Edelman’s book, ‘Change Your Thinking’.

Q. ‘Are you suggesting I tell people my secrets?’
You are entitled to keep secrets, especially when it’s no one else’s business. When making a decision about whether or not to reveal yourself, use commonsense – it’s no use unburdening if you will be persecuted as a result. But if the secret gnaws at you, and burdens you, consider revealing it to a trusted friend.

Q. ‘Should I reveal that I am . . . ?’
I can’t answer that. On one hand, you may feel better after revealing it, because you will no longer have to expend all that energy hiding your true self. You will find it easier to be the person you were meant to be, and be far more relaxed. On the other hand, if you reveal yourself you may encounter problems you might not yet be ready to deal with.
  Seek competent, helpful advice about whether you should reveal fruity stuff about yourself, and when. There are free counselling services available in some countries.

Q. ‘I’ve been lying all my life. It’s a hard habit to break. In certain circumstances I find myself automatically looking for a fib, to protect myself.’
It is like that for many of us. Monitor yourself. Persist. Be alert to your lies, and when you hear yourself lie, retract it. Say to the person, ‘No, that’s not true, I take that back— .’ After a while you will catch yourself before you get the words out.

‘The more honest you are, the more open, the less fear you will have, because there’s no anxiety about being exposed or revealed to others. So, I think that the more honest you are, the more self-confident you will be.’    
His Holiness, the Dalai Lama.

Don’t make excuses. For example, if you pirate music, don’t  justify your actions with excuses. Admit to yourself you are a thief. Be honest with yourself. It’s better for you if you come to terms with your behaviour.

Q. ‘What if someone aims to do something extraordinary? What if they decide to be an astronaut, create an empire, or become a talk show host? The chance that they will succeed is slim. Aren’t they lying to themselves? If they took your advice they would give up.’
  To aim high doesn’t mean we are deluding ourselves. If we think we can achieve something, but can’t, we are simply mistaken. Our judgment might be poor. We can’t assume we won’t succeed; some people do become astronauts or talk show hosts.
     Can you see the difference between the two views below?
     View A: ‘I can give up alcohol.’          (This might be a delusion, but it also might be true.)
     View B: ‘I don’t have a drinking problem.’      (This is a lie to oneself.)