my most used note is likely the Delphic maxims in classical Greek that I like to copy-paste into hashtags, where appropriate of course #Μηδὲν_ἄγαν

For me, it's a note outlining how my home network is set up. local names, IP addresses, SSH usernames, etc.

So many things are going on (including this #Mastodon instance) that it's impossible to keep track of them.