My original question planned for this was a little different from one that Jlong suggested, but I think they go well together, so: answer one or both!

(a) What's something that you paid for, received, was exactly what you expected (not defective or misdescribed), but still felt regret just because you no longer wanted it? That "what was I thinking" moment...

(b) What's been your worst purchase experience, and what all went wrong? I am sure we all have had things go horribly wrong either with the seller or with the shipping service, or the payment service, or all three (Jlong I'm looking at you). For these answers, please let's keep it anonymous for the individual(s) responsible for your anguish here in public.