There is a time to boast:
1. During job or performance interviews.
2. When you are selling your product.
In short, to win people over to the merits of yourself or your product.
The time to be humble:
1. When you are with your colleagues.
2. When admonishing others.
3. When examining yourself to improve yourself.
4. Before God.
Paradox? Hypocrisy? Or just the right action for the right time? Asian modesty errs on the side of modesty. American philosophy tends to incline more to salesmanship. The Bible says to "consider others better than ourselves."
I think the key is truth with love. During an interview, you shouldn't exaggerate facts until it becomes a lie. Just highlight truth. (Though of course, when an interviewer asks you what is your weakness, I don't think it's a good idea to tell them if you have a problem with flatulence...)
It may be the truth to tell what is right, but if it harms someone else, perhaps some things are better not left said, though it may be true.
The tough thing is to balance both. "Instead, speaking the TRUTH with LOVE, we will in all things grow up into him who is the head, that is Christ." A difficult thing to balance indeed, something that takes experience to learn when and how.