Good responses to the thread. Interesting to see what would make a game not fun for someone. Seems like feats and stat generation are fairly big for rules. I am surprised multiclassing didn't come up.
Really? All of those are dealbreakers for you? Some of them I can kind of understand, like players who hog the spotlight or DMs who favour their partner over others, but I feel like some of these are a little excessive as dealbreakers. But whatever floats your boat, I guess (or, considering the thread topic, whatever sinks your boat).
Take advantage on flanking for instance. To me that indicates that the group wants more tactical combat, so a higher focus on combat. Okay, that is not my thing but not a deal breaker. Only, it removes tactics from combat by invalidating creative ways to get advantage. It also invalidates many character's abilities. So yeah, don't think I would play in that game as there are probably going to be other areas that I also find invalidate my choices.
More about who you play with than the exact rules IMHO.
It's called "advice" for a reason, because there's not really meant to be a "global understanding" of the rules, it's only meant to help DMs who can't figure out how to rule on a particular issue by themselfes. This is a game of "rulings, not rules".For me Sage Advice is more of a tool to settle discussions globally once and for all. Often when I ask SA to clarify a rule, this comes from page-long discussions on forums how a rule is meant in which people just couldn't agree on something. SA is basically a judge that says which one of the two+ possible interpretations is the correct one. A DM intentionally going against that consequently is a killer for me, because in the end I want to rely on a global understanding of the rules and not re-learn the interpretation per DM.