I recently got an email with this byte sequence:

\xf0\x9f\x8e\x81\xf0\x9f\x95\xaf\xef\xb8\x8f

That’s U+1F381, U+1F56F, U+FE0F. The last one is a “variation selector”:

https://unicodeplus.com/U+FE0F

My toolkit renders this incorrectly – and so do tmux and GNU screen.

Unicode ain’t easy. 🥴