Most of the problems arise from people not understanding that linq queries return iterators, not collections and therefore writing O(n²) loops. But that's not too hard to learn.
Alas, if you are talking about Linq2Sql or Entity Framework, then of course you have to deal with all the typical ORM problems; but this has nothing to do with Linq.
I think the common sentiment is that we'd all hope to hell that we never have to work on a project so crappy that team members can't understand programming language basics.
