When it's Monday, you've got twenty bucks to last you till Thursday, but you still have to buy the Female Dwarf Gourami and Red C. Wendtii becuase you haven't been able to find them anywhere else..
When you're brother decides he wants to start a tank, and you send him 20 text messages outlining what to look for in a filter, what fish don't mix, etc, then end up going to the store with him anyways.
When your girlfriends sister calls you to help her friend figure out why their new F.P. clownfish and the blue damsel they used to cycle their reef tank are fighting, and despite only keeping freshwater fish, you know that answer.
When you get pissed off at Facebook games for misnaming fish, supplying freshwater plants and only salt water fish, and letting you put bettas and clownfish in the same tank.