I agree with you that honesty is a virtue, but that doesn't necessarily mean you should share absolutely everything the first time you meet someone.
A friend of mine has a good description of what building rapport is. You start depositing little bits of trust with the other person. As time goes by, and you know your trust is secure, you share more.
Looking at it from another perspective, do you have time to reveal everything about you? Hardly, so you reveal traits that will continute the relationship. If you didn't, you wouldn't have a relationship, how would that benefit you?
Isn't your friend looking for the good in you? You're just helping them by displaying it!
Lots of love,