Servers that are fun -
Servers made for building, where the admins are cool and they make sure there's no spam.
Servers made for death matching, where the admins are cool and they make sure there's no starfishry. The build is fun, diverse and interesting.
Servers that are not fun -
Servers made for building, where the admins are stupid kids who are: afk, don't care, and/or are starfishs.
Servers made for death matching, where the admins are stupid kids who are: afk, don't care, and/or are starfishs. The build is unimaginative*1, too big/too small and/or is overused.*1
Servers made for city/family/jail role playing because every admin is a stupid kid who is: afk, don't care, and/or are starfishs. Blockland is simply not suitable for role playing, it has not been implemented in a way that works yet. The only players who find these fun are kids and kids are not fun to play with. (Unless you're a priest, [insert drums])
These are facts based on what I've seen, and my experiences in game.
There is NOTHING fun about a stuffty server full of stuffty builds with stuffty spam and stuffty admins. NOTHING
*1 BF3 in the title, COD: MW in the title, Afghan DM, platform DM, etc.