There are lots of us who feel that way, lol! I have four gifted kids, but none of them is building nuclear reactors in the basement or writing deep, meaningful poetry. Many parents here might disagree, but I think a LOT of that has to do with parental involvement and exposure (which I don't think is bad, mind you; I think it's wonderful, but I just don't have the time and energy and money...). So, we muddle along and are grateful to be in a school system that has offered my kids gifted programs and challenges. Often, my kids seem too "average" to be gifted, but I also think that family dynamics can really affect that. When I'm in the regular classroom, I'm often reminded that my kids are more different than I've realized. When my older children's friends/SOs are around, they comment on how "smart" our family seems. It honestly seems hilarious at times- do we seem extra smart when dd20 is wearing high heels and a mini out in Chicago weather or when sports-obsessed ds8 is going on and on about the Bears' chances? But then I get little flashes of insight that they really are bright (and yes, we're usually as surprised as I just sounded, lol!!). Hang in there, and if you can, hang out in your son's gifted classroom. Unless things are really different where you live, I'm guessing it's just like my sons' gifted classrooms - lots of relatively smart "normal" kids - they still whine, and fight, and goof off, AND have occasional flashes of brilliance!
