Firstly, if we're talking about the Trolley Problem, that's not a behavior paradox, that's a morality paradox. Animals, including human beings, commonly act first and rationalize their behavior later. We can decide after the fact it was ethical after all, decide that it wasn't but was justifed due to circumstances, decide that it wasn't and wasn't, but we'll reconcile it after the fact. Examples like the Trolley problem are not meant to reflect real life and how we behave, rather are contrived in contemplation of the logical mechanisms we use to determine ethical options can become problematic. (Utilitarianism has its own paradoxes.)

Secondly, in fact, human beings are susceptible to paradoxes that can cause decision paralysis, but they tend to be about either survival or high-stakes situations with incomplete information. A common one is when a green, low ranking enlisted person is given a direct order that is illegal. In the US army, our soldiers are educated as to the rules of war, and what constitutes a war crime, and while they are legally obligated to not act on illegal orders, they also know well before they get out of boot they'll be jolly sorry if ever they do disobey an order. Command them to commit an atrocity on the field and they lock up by the dozens. Hence squad commanders know that if they issue an illegal command -- even one based on incomplete information -- it risks unit cohesion. Getting caught in a SNAFU like this is still common, and the enlisteds seldom come out of them well, so it's on the list of counter-recruitment bullet-points.

The same kind of thing also appears in game shows (where its contrived) and in the strategic command chain of command, because a lot of officers do not ever want to be a guy who nuked two million people, even if they're the enemy. And yet those officers routinely got to serve as key-turners to arm (or launch) our nuclear arsenal. (I don't know how the situation is since the new century, if those stations are even manned at all times anymore.)

In the end, we are animals, and typically when we're confronted with moral choices, it's a matter of survival or high stakes, in which case we often don't have the time for measured contemplation on what we're doing. Moral philosophy questions what behavior may be right or wrong according to a given standard, but it doesn't get into how people actually behave. For that, consider psychology and sociology.