bordom, i get bord with stock quickly so end up changing my tanks around alot wiether it be aquascape or stock, i cant decide what i want to keep long term im finally getting my stock how i want it now.... how long will that last though lol... its not fair on the fish and same as above if its rare i buy it then worry about whether i actually wanted/needed it or if i had space for it. so on a whole i guess its my own irresponsibility that bugs me, its too easy to make visiting the lfs's religiously your hobbie, or sitting on here instead of enjoying your actually tank!