One's attitude toward music has some bearing on what they might expect when playing in a group or a jam. If one views music as a group effort, they look for ways they can fit it or enhance what is being played. If music is viewed as a means to show off one's skills, the musician is far more likely to try to take over and play what they want irregardless of what the others are doing. I consider myself a competent listener and a musician of very modest skills. But I have seen sessions ruined by someone who is always trying to show off, and what might have been a great recording or performance ruined by a bass player or other instrumentalist who does not know their place.

I would consider John's tips valid and well stated.