Showing up to the second day of a new job is the choice most people forget is a choice.

The first day is exciting and the second is where people quietly disappear. Something about a new place is uncomfortable enough that the easiest thing is to not go back, and employers see it constantly, which is why simply returning puts you ahead of a surprising number of people. Nothing about it feels like a decision.

If you have just started something and it felt awful, go back once more before you decide anything. Give it two weeks, since almost every job is strange for the first fortnight. If you still want to leave after that, leave properly.