Coffee. Anyone can make a cup of coffee. Making a good and properly prepared cup of coffee, espresso, etc. is surprisingly complex.
I wanted to make myself a simple cappuccino at home. I now have several pieces of prosumer gear, gadgets, fancy beans, and spend my free time reading up on things like coffee grind distribution methods, hacking my machine to add a PID, and other such ephemera. On the plus side, I'm saving several hundred dollars a year on my coffee habit despite all the toys, so there's that.
This goes for homebrewing (beer/wine) too. If you can make oatmeal you can make beer, but if you want to make the same beer exactly the same over and over it is very complex. The fact that Budweiser tastes the same all over the US and is made in 12(?) different locations is a testament to how good the brewers are (even if beer snobs don't like it).
As for coffee, even the foam on top of an espresso is complex.
I wanted to make myself a simple cappuccino at home. I now have several pieces of prosumer gear, gadgets, fancy beans, and spend my free time reading up on things like coffee grind distribution methods, hacking my machine to add a PID, and other such ephemera. On the plus side, I'm saving several hundred dollars a year on my coffee habit despite all the toys, so there's that.