In your OP I noticed two things that came up over and over: You pretend a lot and you compare yourself to others a lot. Both of these are ways in which you self-sabotage.
First, don't pretend; just DON'T do it. Be yourself. If you don't know who that is, check this out.
What is The Work of Byron Katie?
Second, stop comparing yourself to others. There is always -- and I really mean ALWAYS -- somebody funnier, smarter, savvier, better looking, skinnier, shapelier, stronger, et cetera than you are. Embrace everyone around you for who they are.... and most importantly embrace yourself for who you are.
Learn to listen. Don't worry about what you're going to say next or what everybody is going to think after you say whatever you're going to say next. Do you see what you're doing when you do this? You're projecting several exchanges into the conversation and deciding way ahead of time that you're going to bomb and everybody is going to look down on you. Don't do it. Just flow with the conversation and most importantly, really listen, really absorb what the other person is saying and respond to that with genuine sincerity.