"Proud of you" is so tricky and (for me) flirts with condescension. To me it sounds suspiciously like "you have pleased me" and therefore I don't much like when people say it said to me and I tend not to say to my kids or anyone else. It pushes my buttons much more than other compliments. I like specific compliments that are about something I have done. For example "the presentation was really clear and concise, I left with a better understanding of X than I'd had before" is the kind of compliment that makes me feel proud of myself.