Coffee.

I blame James Hoffman entirely.

Within a year I went from:

Drinking instant coffee at home, but really enjoying "proper coffee"

To

Buying a cafetiere (~£15) + preground coffee

To

Buying a Nespresso (~£60 on offer) + pods

To

Buying a budget espresso machine (~£120) + preground coffee

To

Wasting my money on a cheap manual coffee grinder (~£50) + beans

To

Immediately replacing it with an entry level Sage grinder (~£170)

To

Buying an entry Level "proper" espresso machine (~£700)

It took me a good 2-3 weeks of practicing and dialling in before pulling a good shot of coffee that I'd actually want to drink, but by that point it was also about learning a new skill, learning how different aspects of the process affect the end result and learning how to make all sorts of different espresso-based drinks.

My girlfriend thought I was nuts at first, but a year or so later even she agrees it was worth the investment. I still for the life of me can't get the hang of latte art though.

The problem is now though that I'm a waaaay more critical of coffee from coffee shops, because I spent a long time making bad coffee whilst learning!