Yup, it's the problem space that is hard, not the implementation. A good way of seeing this is to look at languages that have "solved" concurrency issues, such

Yup, it's the problem space that is hard, not the implementation. A good way of seeing this is to look at languages that have "solved" concurrency issues, such as Erlang. I mean, sure, you won't have concurrency problems in Erlang, but that comes at the price of only having immutable variables... I think the problem with concurrency is that certain things that we do in sequential programming are provably impossible to do reliably in concurrent programming. So we end up using traditional languages, such as C/Java/Python, which are very error prone because we can only correctly use a subset of the language features, and it's not clear what the subset is, or we can use a language such as Erlang, which explicitly enforces concurrency-correct code, but then we find programming in such languages very restrictive. Meh. I'm not enough of a language wonk to figure this one out!