The thing I love most is the fantasy, supernatural stuff but these also have to tag along with a a good plot. One factor can really make up one another. For instance, to connect to an audience you need character development; without character development you can't really feel for what's going on. You need that sort of emotional connection, which may seem weird but true either way.
I also noticed that a lot us also take the Art into account as most of us really go 'argh that episode wasn't drawn well'- which shows that it is a factor. Stuff looking weird just makes it look... well... weird, funny
An anime needs to make you want to watch more so suspense is really important, you need to be at the edge of your seat, otherwise the anime is just boring. That's why we complain about fillers

There's no suspense
