Depends on the type of model it is, a lot of the time. Anime egirl/eboy-styled avatars tend to be some of the worst offenders (often kitbashers who don't know any better), while furry avatars tend to be really well optimized most of the time.

If you aim for medium, that's generally sufficient.

I hate to tell you this, but the previous one was, too.

Dragonsong's Reprise (Ultimate) in Final Fantasy XIV. It's you and seven other people versus nineteen minutes of grueling, bonkers-difficulty fight across six phases where individual mistakes can easily cascade into a full wipe and reset back to the beginning.

But now I can tell people I'm an ultimate legend, btw.