If you're debating whether to read the letter your time-travelling friend wrote you, "What the hell?" is an okay justification. However, if you're about to utterly ruin your diet all week because you had a tiny slice of cake on Monday, maybe don't give in so easily.
As advice site Choose Better Life explains, the What-the-hell effect occurs when we break our habits a tiny bit, so we decide "what the hell?" and go completely bananas ruining those habits. It happens when you missed working out at the gym one day, so you decide to skip it for the week, or when you swore you were going to be productive, but you ended up on Facebook, so you decide to stay there for three hours.
We figure if we screwed up already, we might as well keep screwing up. That thinking, however, is a trap:
The what-the-hell effect is the feeling you get when you've already exceeded your preset limit and feel that since you've already failed, you might as well fail spectacularly...
...When you miss a goal or exceed a limit, be gentle on yourself. Don't catastrophize. Armed with this knowledge and awareness, you'll be able to make better, more informed choices as you move forward.
The what-the-hell effect's power really comes from our belief that the momentary screw up symbolises our complete failure. Of course you ate a slice of cake on your diet. Your diet is a total sham anyway, right? So, what the hell? Why not go crazy?
However, your habits aren't ruined just because you failed to meet your ridiculously high expectations once. If you missed your goal today, try again tomorrow. If you got procrastinated for a bit, get back on track as soon as you can. By treating minor lapses like the tiny issues they are, you're better equipped to stay on track with your habits. Just don't go causing any time paradoxes.