Certain points of the game will cause a lock-up, freeze, and/or crash. Often without any warning.

Sometimes, I'm lucky and get a message like this:
An unexpected error has occurred. Exiting FINAL FANTASY XIV. 2018-12-25_17:25

ffxiv_dx11.exe+31BB3F
With that last line being repeated seven more times, with changing letters.

By certain points of the game, I mean places like Ul'Dah. I remember getting to the point that logging in at the Alchemist's guild during the Starlight Celebration would immediately crash, and only getting out of that loop by using the few seconds I had before it closed to get out of there.