One reason is I simply forget how! Maybe it's fear I won't be accepted anymore if I am truly myself? Maybe people will think I'm weird, unregenerate or ugly or gross? Mostly unregenerate. Always trying to prove myself to myself and to others and when they approve of me, I approve of myself. I feel Jesus leading me to freedom in this area now. I wanna be me. I don't want to impress anyone anymore. It makes love and relationship really hard, if not impossible.
But the fear of being myself is one of my biggest hindrances to brotherly love and enjoying other peoples company. Sometimes I want them to go away so I can relax and be myself. I can't love others if I don't accept the person I am. Nor can I allow others to love me. Well, not the real me anyway. And so that can breed bitterness towards even our friends because we refuse to relax and be ourselves. It makes us bitter because we're so stressed out every time we're around them and we just wanna take a break! And so we begin to despise their company because of our inability to be free to be ourselves.
I don't wanna avoid anyone because of exhaustion of trying to present some beautiful image of myself to them. I wanna let them in to my life without trying to be a people pleaser.