I think writers just liked that dynamic, and wanted to write that in since it was interesting to explore. It made sense for the time since Hal was neither good nor bad and they needed a character to be the doubting Bruce. Thankfully it's either gone or reduced to a simmer by now. I enjoy how it changed so that Batman just doesn't vibe with Hal's brash, improvisational tactics and Hal isn't impressed by Batman's schtick. That still makes sense and fits both characters, but is no longer based on "ET" or "ZH."