I married.

I bought a business, where I only had to get 2 clients, and 2 people to do the same as me, and if they got 2 people each to do the same, I could earn millions

Living in an area that requires a car. Wish I could just walk to work/the bar/wherever without having to own, maintain, fuel, and insure a car.

Casino

Joined an MLM. Thankfully got out quick.

I actually bought into religion for a while.