Probs low hanging fruit for this thread, but vinyl collecting.
Started around 2011 by going to charity shops and second hand stores to find bargains. I used to be able to spend £10 a week and get 3/4 new (to me) records. Some were great ,some were trash, but that was the fun!
Then I started getting specific records, building towards band discographies... next thing I know, I'm dropping £25 per record for two bootleg records that were definitely not worth the price. Was a watershed moment and one that made me take a step back.
Ticked over for a year or two, next thing I know vinyl records are now in Asda, Tesco and Sainsbury's. Every new release comes on vinyl, and they're now £25+. Charity shops are now just full of junk vinyl, and all the second hand stores now charge £25+ because their pressings are "original"... all the fun is now gone.