I think one of the most common and harmful thought we all have is "I can be excessively self-indulgent now as long as I make up for it later". It is at the root of most drug addiction, procrastination, failure of greatness, weight problems, and social problems. A habit best broken.

@freemo As a non-sequitur, here is an unrelated graph explaining the Dunning-Kruger Effect, shorthand for “incompetent people think they’re much better than they actually are”.