Well I've got one that's not nearly as bad (financially) but looking back has caused me tons of problems. Getting a degree in something that you're good at (and at the time had plenty of jobs) but that you hate doing. Trust me going to work everyday to a career you hate isn't worth the paycheck (unless you make enough to retire after a couple years, which I didn't)...
"A dude who owned a small convenience store in our town spent like $20,000 on fidget spinners. He was posting for like a year begging people to buy them as he would lose his business and his marriage was falling apart due to it."
Well I've got one that's not nearly as bad (financially) but looking back has caused me tons of problems. Getting a degree in something that you're good at (and at the time had plenty of jobs) but that you hate doing. Trust me going to work everyday to a career you hate isn't worth the paycheck (unless you make enough to retire after a couple years, which I didn't)...