Why do I have this feeling?

Kala mo kung ano nho?.. This is about how I shopped, I have a strange feeling, when Im at mall and there's something I want to buy, for an instance a dress, well at first Im so sure to take it..but at the end, when I already have it and bought it I just felt regretful, I don't know why..maybe because I lose my money! lol. So funny right?. But its true. I dont know why I have this illness. haha.