Malcolm Ocean defines a thought hook as:

...a module in your brain that gets activated by you thinking/saying/hearing a certain phrase or structure of sentence. [...]

So one example (that will be familiar to some CFAR alumni at least) is when you encounter the word “later” and your brain instantly responds “THAT’S NOT A TIME.” Val, a CFAR instructor, while teaching a course on the planning fallacy and contingency planning, has described how he’s very averse to the word “later”. Why? Because it’s dangerous. It looks like a time but doesn’t act like a time. You can schedule something for “later” but that won’t actually cause the thing to happen because later never comes, even though the word works grammatically and type-sensitively (“schedule for X” requires that X refers to some point(s) in time, which “later” does).

I seem to have managed to install in myself the thought hook "if something feels uncomfortable, but doing it involves no real risk, then the discomfort is a reason to do it". This has been a useful way to get myself to do comfort zone expansion. So far, it has caused me to do things like 1) walk a route that I've sometimes avoided because I sometimes run into a neighbor coming the opposite way and I feel social anxiety over not knowing the right distance for making eye contact and saying hi 2) go into a store selling women's clothing and shop for a new dress 3) wear dresses and cat ears in public 4) make food when I'm at home and feeling sufficiently low on energy that I'd rather just go to a nearby fast food place than prepare anything myself.