I have been playing D&D 5e for a number of months now, just with a group of friends of varying experience, and I'm running into problems whenever one of us DMs. I suppose you could say that I like powergaming, and because of it, the DM feels he needs to do stuff like the following to keep me in check.
Here's are some examples from our first session (hopefully of many):
We are making our characters.
Me (Power Freak): "Are we rolling for our stats? or using the point/buy system?"
DM: "You're welcome to roll, but you're not allowed to keep anything above 16."
Me: "What's the point of rolling then?"
Our party has two players with the ability to provide food if the land provides.
Using our rations is the only way to feed our party, and we're only allowed to forage when we're setting down for the night.
If we do find anything, we can't cook it immediately, instead it has to be stored for a day to 'turn into rations.'
I made a level 1 rogue.
Our group had just bought cloaks that when worn, make everyone have disadvantage on perception checks made against us.
We are in a combat with 6 goblins and a goblin boss.
Me: "I'm going to sneak away from the group a ways to stealth."
Rolls a 16 + 7.
DM: "The goblins never knew you were there."
Other PCs take their turns.
Me: "I'm going to go in for a sneak attack with my dagger on the big guy."
Rolls a 6 + 3.
DM: "Before you hit, the big goblin reaches out and grabs one of his minions, using him as a shield."
Me: "How did he know I was there?"
DM: "He doesn't have to, it's a game mechanic."
Unfortunately, with this being the fourth or fifth time we've butted heads, I tune out and stop listening to the DM, and on my next time I ditch the party. (I am fully aware that I'm prideful and a sore loser, but I can only take so much.)
After the combat I looked up the ruling on the boss goblin, where it states that the boss needs to see the attacker, but since the combat is over, it's too late.
So, my question is, What should I do to eliminate these problems since I disagree with the DM's rulings?