Not that Concurrent!

Concurrency is, in the literature, often used as a noun with a range of strengths: there is more or less concurrency; it is more or less limited; it may even be seen described as complete. In trying to discuss multi-threaded programming with programmers who state that they program single-threaded, it is important to communicate that they may program less concurrently, but probably not as non-concurrently as they believe. What are the factors that increase concurrency and which factors are orthogonal to the degree of concurrency? Does a Go language goroutine increase it and is a C++ object orthogonal? Will the CSP paradigm generally enable increased concurrency? Is the CSP paradigm of communication-with-synchronisation itself orthogonal to the degree of concurrency? It is also important to understand the term parallel slackness: does it introduce or enable more concurrency? And what about atomicity?