Also, people aren't used to receiving compliments. Compliments are often just landmines of expectation wrapped up in pretty packages. Women, especially, are wary of compliments from men, and men from other men. (Is there a man alive who wouldn't enjoy one from a woman? Maybe. Not in my experience, but I can't imagine it's the universal response, either. Women complimenting other women is...unexpected, but usually a pleasant surprise.) Ever notice how people's first impulse is to argue with a compliment or deny they're worthy of it? The only cure, I think, is more practice at giving and receiving them. Good start!