What's the most expensive impulse purchase you've ever regretted?

I built BuyLater because of a €280 jacket I bought at 11pm, wore once, and still feel bad about two years later.

The app is simple: instead of buying something the moment you want it, you add it to a list and come back later with a clearer head.

That's it. What I found is that about 60–70% of things I added to my own list I ended up not buying at all.

The impulse just... faded. Curious what brought you here — and what's the purchase you wish you'd waited on?