My rule for general social situations is: I won't ever go to any event where drinking is the main or only purpose of the gathering. I'm ok with alcohol being around, in a peripheral sort of way, but I'm not ok with being at an event where the only goal is to drink and get drunk.
Generally, this rule keeps me out of bars most of the time. But, I might go to one if I'm with my husband (who doesn't drink around me) and we are just going there to eat dinner, watch a sporting event, or see a band, as opposed to going there to drink.
I won't go to anything like a happy hour, or a party or bar gathering where I know people are *only* going to be drinking, or a wine or beer tasting, or anything like that. If alcohol is center stage at a certain event, then it's no place for me to be, whether it's in a bar or not.