I'll try to give a serious answer myself.
For me, what makes football appealing is that possessions and scores are important without being too few and too far between. With basketball, scores come so frequently and are worth so few points that I find it difficult to be engaged until the fourth quarter. With soccer, scores are so infrequent that I simply find the game boring. If you don't score, your possession was essentially meaningless, and there are a lot of meaningless possessions in soccer. Sure, there's plenty more action in both, but it's large uninteresting, ultimately un-engaging action.
With football, there's much more of a balance. In most games, scores aren't rare by any means, but they are significant enough that each score notably tips the odds of winning in favor of the team that just scored. And even if you don't score, your possession can still be a meaningful one. Simply changing field possession is enough to make a major impact and perhaps keep the other team from scoring. There's an easily noticeable layer of strategy in football that I think goes deeper than most other sports; it doesn't simply deal with the current possession at hand, but also in determining the outlook of the rest of the game. You've got a fourth down and 2 on the 39; do you go for it, kick a field goal, or punt it? The decision you make doesn't affect whether you just score that drive, it also affects field position drastically if you miss it, which then drastically alters the likelihood of the other team scoring. That just doesn't exist at an easily appreciable level in in any other major sport that I've watched.
There is quite a bit of slowdown, but I'll take 20 or so combined minutes of all meaningful action compared with 90 minutes of people running around a field and then maybe 3 minutes of action that will actually determine the outcome.
