Earlier quoted context omitted.
This attitude seems a little silly to me—being "extra vigilant, pedantic and strict" about happy-path code would necessarily imply the same about "exception and error paths". Generally speaking, bugs mostly appear in a binary fashion and not in varying degrees—ie your code either reflect expected behavior or doesn't.
You'd be surprised at how many await 's it takes to produce a try/catch . The attitude of being extra vigilant, pedantic, and strict around exception and error paths forces the happy path to be as well defined as it possibly can be given the requirements. It's defensive programming. Assume everything will break in ways you don't know about when writing it. Especially true for async/await code. I don't find it silly.…
This would necessarily presume applying the same attitude towards the happy path—you're describing something short of that.
Or to put it a different way: defensive programming necessarily implies a skepticism that you even are sure what the happy/error paths are!