I thought debugging was table stakes. It isn't always the answer. If a lot is going on logs can be excellent (plus grep or an observability tool)

However debugging is an essential tool in the arsenal. If something is behaving oddly even the best REPL can't match debugging as a dev loop (maybe lisp excepted).

I even miss the ability to move the current execution point back in .NET now I use Go and JS. That is a killer feature. Edit and continue even more so!

Then next level is debugging unit tests. Saved me hours.