One somewhat related theoretical observation about concurrency is in some article by Dijkstra (I don't remember the reference right now): he says that debugging using traces (essentially printf) does not work for concurrency, since it is projecting multidimensional data (data present at the same time in multiple processes) unnecessarily linearized onto a single dimension (a sequence of printfs) and then trying to make sense of what is happening. It may not work, even if you print timestamps.

His view was to promote theoretical proofs of correctness of concurrent code, rather than debugging, but to me at least, this is much more difficult.