I mostly board alone, I'm just not very good at boarding in a group because I will completely vear off if I see something shiny I want to hit, regardless of where everyone else is going. Most people are pretty freindly though on the lift, and since your both relatively like minded people, (your both snowboarding/skiing) I find it's ussually pretty easy to have good conversation. So, for me I guess I get my social interaction on the lift.
I agree though that on a certain level it helps to ski with other people who are at or above your level, because it will subconsciously push you to get better.
PowderHound and TreeNinja