No matter how great a game is, if the team you're rooting for (especially if they're a team you live and die by) loses, then it's bound to leave a sour taste in your mouth.
Also, while I'd prefer that my team won every game in a thrilling fashion and that every game was a classic, I'd take winning shitty games if it meant winning a championship. 50 years from now, it's not likely that the quality of games will be remembered, but just the image of whomever wins it hoisting the trophy in the air.
Pretty sure that if the Red Sox lose game 7, their fans would rather have won a bunch of shitty games as opposed to 3 very good/great games just to force a 7th game. Sure, you can take some pride in your team being the first to ever do that and remember the games that they won fondly, but they don't give you a trophy unless you win the World Series. I wouldn't call anyone who's a fan of either team who'd rather win a shittily played game than lose a classic less of a fan than anyone else. Having a team to cheer for clouds your judgment.