It's the Monty Hall problem effect. When you take an action, you choose from a small set of options. When you stay with the status quo, you are following a Markov chain than has not been narrowed by your choices (which is worse on average).
The point the parent is hinting at which can apply although I'm not prepared to argue for it as a general rule is the following: If you are in a not good situation (and e.g. you're torn about changing your job as an example given in the OP), I can believe that making any reasonable change is better to just plodding along with the status quo.
In a similar vein--and I've run into this a bunch with project management--making a decision (any decision!) is often better than a status quo of deferring and studying for longer.