My issue with praise was not downplaying someone else's compliment. I've learned to just say "thank you" gracefully and not attempt to qualify their statement. Part of this is embarrassment - I like compliments, but they also put the spotlight on you, and I hate the spotlight.There is also the whole thing about being praised and being the centre of attention. I like it when other people notice what I've said/done and tell me so, but at the same time I'm not comfortable pushing myself out there. It's a real conundrum, this craving for validation yet not wanting to ask for it for fear of being inauthentic. I guess it's because we don't do things that are important to us in half-measures. When we put ourselves on the line for something (like commenting in a thread), we go all in so anything we perceive as an 'attack', no matter how minor, will hurt like hell.
And yeah, when I've put myself out there & put my heart into something just to have it/myself criticized or rejected, that is a hard blow. When you have a couple of those in a row, you can start to doubt yourself and your capabilities.
Oh, I thought of something else : self-deprecating humor. I think sometimes this does not register with people and they think you are serious .