I haven't served in the military, but I have been onsite in awful places at someone else's schedule and whim.

Getting extended arbitrarily is horrible. The only thing worse is when they let someone else go home early, and force you to stay for no real reason. (Not even drawing straws or similar.) That genuinely broke me. Doing this to people is cruel, full stop.

(Fortunately, for as bad as it was for me, it did at least make it impossible to ignore my mental health, and was the beginning of a long, long road of treatment.)