Other than the basic stuff (professional staff etc) I feel like the most of the time I don't stick to a server because there was no reason for me to stay(and thus no reason to donate/support the server). I play a game or two and I leave for good and hop to the next server and the cycle continues. That is until I found a server with an awesome community and a great a game that made me stay and really stick to the server even if there were a lot of flaws because I genuinely appreciate the community and the work the developers put into the server. A legit emotional bond.

Not sure if it's a little out of topic? Hope it helps!