I usually mention, a few times, how I'd like the item, to soften it's purchase. The remark always is "why do you keep talking about it. If you want it, get it. You'll know in time if it was a good choice."
Strange thing is after all these years I still feel uncomfortable when buying something for myself. We've always been thrifty, by need and by nature, the kids are long gone, no debt whatsoever and yet I still go through this struggle with my conscience. I think the aforementioned remark means "you made the decision, live with it".