All musicians practice ear training constantly, whether or not they are cognizant of it. If, when listening to a piece of music, a musician is envisioning how to play it or is trying to play along, that musician is using his or her 'ear' - the understanding and recognition of musical elements - for guidance.
Steve VaiThere's very notable dynamics in all of the collaborations I've done. It's hard to say if one is more important than the other, but if I had to think of all situations and point to one band that I enjoyed most it would be when I was eight years old. I had a band with my little sister and the kid across the street. We sat around all day playing music and it was bliss. I didn't have any expectations or do it for anyone or worry about selling an album. That was really my favorite band. We were called Hot Chocolate.
Steve Vai