Working from home, downloading modern (60, 80, 100, 150GB+) games.
Having internet at this speed means that in most cases, your downloads are bottlenecked by someone else.
It also means you can do a virtually infinite amount of bandwidth consuming things concurrently and there's always bandwidth left over to maintain high quality of service for streaming, gaming, video calls, etc.
Coming from xfinity 1200/35 cable to a symmetrical 3500mbit fiber line, my internet has never felt more reliable. Thats because I can just do whatever I want whenever I want, as much as I want and it never causes an issue for anything or anyone else. No more yelling "are you downloading something??" From the other room because their stream started buffering. No more complaints about video calls being laggy or dropping because I was uploading something for work.