I love the challenge. I love the huge diversity of life from worms to bugs to fish to coral to mushrooms etc. etc. I like finding new critters and life forms in my tank that I never knew existed. I like propogating my own corals and "making" my own LR
by just allowing a bare rock sit in my tank for a while. I love all the mechanics and contraptions (ie. pumps, skimmers, sumps, hydrometers, tests, meters, etc.).
I love to tinker.
One day I would like to have a FW
planted tank so I can experience that challenge. An African Cichlid tank sounds fun too.