If Reddit implemented tagging and tag filtering, the quality of the place would improve immediately. It's possible to blacklist subreddits, and maybe users, but I would love to have an easy way to remove entire topics from my front page.
I can't stand GG nonsense and its derivatives, but I have to put up with it, because it shows up every now and then on gaming subs. I could filter keywords, but I'd have to find what words are used in titles I don't want to see, but not words that I want to never see in a title. People throw fits when characters boobs get smaller, but I don't want to never see "boobs" in a title.