Imagine how pissed off you would be if you somehow ended up in Middle Earth in time to help, but you didn’t speak Westron. Or Sindarin. Or Khuzdul. All you have are proper nouns, and some random phrases like Mellon, and Amralime, and, oh yeah, the inscription from the One ring. because that’s going to go over well when you start spouting off long forgotten verse in the black tongue of Mordor….
So instead of eloquently explaining yourself and saving lives and falling in love with a character of your choice, you have to chase them around like a slightly more verbose Hodor, trying to learn a language and keep the dumb bastards alive.
These are the thoughts that keep me up nights.