I'll admit the proudest I've been as a Father is when my Son took me out to dinner, last year and this year. It was as if I had seen him grown up for the first time when he took me last year, that I had did at least part of my job right.
Probably the other is as a published author, my adult children reading what I've written. They seem to like it a lot.
Of course, the Grandchildren are nice once in while also :-) It's especially nice to spoil them and send them back to your Son/Daughters to pay them back for all the things they did to you while they were growing up.