Hypothetical situation.
A close friend is about to start a new campaign, but you're not too happy about a couple of his design decisions; you feel that they will detract from your enjoyment of the game. You've spoken to him about it, and his reply is, in a nutshell, "I have a specific vision for my campaign. I want you in it, but not so much that I will compromise a little to make you happy." You're shocked because you've never imagined a time that you weren't gaming with this person.
You're good friends. You've gamed together for years, but now he's standing firm on his decision. Do you part amicably and not play together anymore? Do you try the campaign despite your misgivings? Do DMs have a responsibility to make some compromises? Do friends?
After discussion goes nowhere, what do you do?