I recently had to debug an issue which required a lot of familiarity with HTTP to debug. There were a lot of random workarounds to the problem (“if I disable feature X it works”) but only when a developer clearly articulated the exact problem with the HTTP response was it possible to trace the error to a consistent reproduction case. The underlying lesson is one I’ve learned at least a few times now. When working with web APIs there will be times where things break at a level where you will be completely helpless unless you know how things work underneath all of the frameworks, toolkits, and client libraries in your application. So learn HTTP, damn it.
Way back in late 2010 I was lucky enough to visit the remote Google office containing the office of Vint Cerf. He wasn’t there, and apparently spends much of his time traveling, but I still felt honored to be able to see his workspace, knowing that I had the privilege of working in the same company at one time, the same cheaply printed nametag on his office wall as the one which used to mark my own cube in Mountain View.