Doing X number of complicated routine things at once, in general, is infinitely easier than any situation where you are suddenly told "part of your system isn't reliable, now come up with a new model of what you can trust on the fly".

It boggles me how people can't put themselves in the place of someone in the latter situation. Like, even if you haven't crashed a plane, haven't you experienced something similar on a small scale? Haven't you observed other people with such problems?