When I watched Steven Universe, the main draw for me in the first 10 or so episodes was the art and animation style, and the actual substance seemed to really kick in around episode 13 or so. As the series progresses, they do a really good job at building up suspense over certain future events, going in depth into multiple emotional conflicts, giving many characters massive development, and providing really nice atmosphere. Granted, the way they handle overarching plots IMO isn't the best since it can lose focus sometimes, and the quality isn't particularly consistent, but most eps have at least one or two things worthwhile enough in my book. And Steven himself does become a lot more charming in all regards over time. However, if you still don't like it even after taking these things into account I wouldn't argue with you. As for Spongebob, many people felt the show in its prime had a sense of quotability in their humor, largely because of just how many jokes are fired every minute in the better episodes and how ridiculous some of it comes off out of context. That, and the humor was for the most part quite varied given the stories and the colorful characters. I do agree the show isn't the funniest I've ever seen, but I think the reason it became as popular as it did was specifically because they threw so much humor out there that most people were bound to laugh at a few things.