I remember having aggressive reactions to sites that insisted that my password couldn’t be longer than 16 characters.
I also remember one time I changed a customer’s AOL password then I found that I couldn’t log back in. IIRC their password changing system allowed one to type in passwords as long as you liked but promptly truncated the password without saying anything, then the standard login system would accept passwords as long as you like but didn’t auto-truncate the password. Seriously… go fuck yourselves.