My obsession is slimes. I love slimes and everything slime Slime balls are good for sticky pistons and soon to bee good for slime blocks which will revolutionize redstoning and parkour. Bow to the slimes, for their slimey goodness will bring you happiness. (Plus on Mineplex slime is my favorite class and can be very OP muahaha)
I personally think that obsessions come naturally. Nick's melon obsession for example, he just really loved melons. Now he is a melon god. It just comes to us if we are attracted to something