It is the obsession itself for sure. I used to keep C.A. cichlids exclusively. Jags, Dovi, Beani etc. Then I realized I didn't have to limit myself only to fish that would kill each other when I turned my back. Now I am obsessed with Hillstream fish and barbs. I would never have though that after 40 plus years I would end up keeping loaches and barbs. I still love to see the big nasty stuff but it is no longer for me.
I've discovered the same recently. I have a 30 gallon planted with snails and crabs, it's incredible, my favorite tank.