in the world of front end dev always expect the unexpected. the amount of head-scratching moments i've had....lost count. i think the worst and most frustrating type of "bug" (not really) - is the "reload - no update" issue. not sure if it has another name. its when you make some change, reload the browser but the update is not reflected :D - usually very trivial but often times the straw that broke this camels back.
Bonus points if it’s combined with an actual bug and you don’t realize hot reloading broke, so you think none of your fixes are working, when actually the one you tried first (and rage deleted) would have actually worked the whole time if you just refreshed the page.