I have to maintain perfect rhythm, impeccable coordination, to stay in the pocket
It can be hard to do that when the only person accompanying you is yourself.
and other times it's just as hard with an orchestra. infinitely moreso, at times...
Two things're for sure If you can't play in rhythm with others It's probably easier for you to play in rhythm with yourself. and If you can't play in rhythm with yourself It's probably easier for you to play in rhythm with others.
But if you're not in time the only way you will be is if someone falls out of it with you