Originally Posted by dru-zod2501
there is a very very fine line between Stan's cameos being relevant and irrelevant IMO. Some make the cut, some don't.
None are relevant, all the films would work without him cameos thus making them irrelevant. They are there as a small easter egg to fans and to give him a bit of involvement with Marvel Studios.
Personally my favourite was in TIH, simple but really nice.