Maybe it is just because you are not used to be with other people? 
No I'm joking, I guess this is a common phenomenon. I haven't noticed this for me though, I grew up playing platformers together with a friend of mine, I tried to beat the level and when I couldn't do it he tried and vice-versa, and we commented on how to do things and tried to help each other.
Actually, those are still my best gaming memories, it is damn great to play a single player game together with a friend, enjoying the story together and stuff.







