Hello!
I have a GCC and everytime I walk in the room he starts bobbing his head...? When ever someone comes to the house he starts bobbing his head he never stops lol. Is it normal?
I've never had a GGC conure, but I've met several and they would often bob their head in excitement. It's extremely cute. Bobbing can be for several reasons though, hormones, aggression, and excitement. The difficult thing about birds is that their aggressive behavior and excited behavior can be very similar. I assume yours is doing so from excitement though, as you aren't asking about biting too lol.
If you're still unsure try taking a video, videos help so much with behavior questions. It allows us to see all the body languange rather than what is only described.
All three of my parrots do that when excited and is a natural behavior .We call it the HAPPY DANCE, and applaud when they do it and they have all learned what it means and get even more excited. My quaker also really gets going and squawks at the same time if you are telling him to do the HAPPY DANCE and clapping . It's cute
Gilbert only head bobs at certain toys that really excite him (luckily, his newest toy is a big head bobbing toy, haha, i guess he is happy with my selection). I think your bird's head bobbing does sound like a happy/friendly/excited bobbing.
If he is doing this for several hours at a time, there may be something going on other than excited. When you say "he never stops" are you exaggerating a little? Mango does this a lot, but not indefinitely.
My roommate's birds do this when they like who comes into sight or if you are eating and they are begging. They also curl up a cute little foot and tilt their head to one side to further beg for food. ( Something for my foot, please? )