Also "need". There's always another option, and pretending sufficiently bad options don't exist can interfere with expected value estimations.
And "should" in the moralizing sense. Don't let yourself say "I should do X". Either do it or don't. Yeah, you're conflicted. If you don't know how to resolve it on the spot, at least be honest and say "I don't know whether I want X or not X". As applied to others, don't say "he should do X!". Apparently he's not doing X, and if you're specific about why it is less frustrating and effective solutions are more visible. "He does X because it's clearly in his best interests, even despite my shaming. Oh..." - or again, if you can't figure it out, be honest about it "I have no idea why he does X"
I think any correct use of "need" is either implicitly or explicitly a phrase of the form "I need X (in order to do Y)".
We recently established a successful Useful Concepts Repository. It got me thinking about all the useless or actively harmful concepts I had carried around for in some cases most of my life before seeing them for what they were. Then it occurred to me that I probably still have some poisonous concepts lurking in my mind, and I thought creating this thread might be one way to discover what they are.
I'll start us off with one simple example: The Bohr model of the atom as it is taught in school is a dangerous thing to keep in your head for too long. I graduated from high school believing that it was basically a correct physical representation of atoms. (And I went to a *good* high school.) Some may say that the Bohr model serves a useful role as a lie-to-children to bridge understanding to the true physics, but if so, why do so many adults still think atoms look like concentric circular orbits of electrons around a nucleus?
There's one hallmark of truly bad concepts: they actively work against correct induction. Thinking in terms of the Bohr model actively prevents you from understanding molecular bonding and, really, everything about how an atom can serve as a functional piece of a real thing like a protein or a diamond.
Bad concepts don't have to be scientific. Religion is held to be a pretty harmful concept around here. There are certain political theories which might qualify, except I expect that one man's harmful political concept is another man's core value system, so as usual we should probably stay away from politics. But I welcome input as fuzzy as common folk advice you receive that turned out to be really costly.