I've lived with my best friend for the past four years, even though this summarizes him perfectly. Throughout high school and before, it was exactly this. When it was just me and him, we were best friends, joking about childish stuff, having a genuinely good time and not an ounce of snark in sight. He would be a genuinely nice person. To this day, we still have the same relationship and I still consider him my best friend.
When there is "an audience" however...
He will change from my friend into basically an abusive asshole. Everything that comes out of my mouth I have to overthink before I say it, or he will "use it against me", in a snarky making-fun-of-me way, a "that-was-an-idiotic-comment-and-you-should-feel-bad-for-saying-it" way, or a "fuck-you-no-one-cares-what-you-think-you're-stupid" way. He doesn't do this to nearly the same degree with our other mutual friends. Frankly, it's gotten to the point where I can't even drink around him and our other friends(who don't pull this petty bullshit) for fear of "retaliation". It really sucks. Yes, I can be too sensitive to these kinds of things, but when it's every fucking day in the place you live it starts to wear on your soul. I moved in to what used to be his grandparents' apartment building with him and two other friends. So basically he's had "the right" to be a complete bossy ass when he wants to be and justify it in his own mind, because it's "his place". Granted, I'm not the cleanest person in the world(none of us are), so I may deserve a bit of "reminding" sometimes to keep things clean, but there was even a time when he would bang on my door at 10:00am if I wasn't awake yet because "he wasn't going to have a loser who sleeps until noon living with him". I do enough micro-managing and overthinking if I'm a loser for myself. I don't need another perspective forced on me, especially one so hostile and unapologetic. Though some of the best times of my life have been spent here these past few years, come August when the lease is up I'm so glad I won't have to live here anymore. I don't like to get off a stressful day at work just to be ridiculed and given shit because he's insecure about himself. I can't live with every word that comes out of my mouth examined, picked apart and thrown back in my face anymore. It's much better living in separate places and hanging out with him on occasion, because then he can't pull this authoritative bullshit.
That said, I still consider him my best friend, and I know if I was in a pinch he'd help me out in a heartbeat. He has many times. I just have realized over the years I need more time to myself to boost my self-confidence, and I don't get that living here. Every day i feel a little more stepped on. I don't know how much longer I can deal with it. I think I need more distance.