The only thing that can prevent me from accessing htop, is a kernel panic.
Because, even if the Desktop Environment crashes or freezes (Can't even remember the last time that happened), I can always switch to another virtual console with Ctrl+Meta+F2, login and run any program from there, including starting another DE instance.
And in the equivalent of a kernel panic in windows (BSOD), the Task Manager is inaccessible as well.