Usually, you want to always connect to a particular machine with the same username. With PuTTY, it would seem that there is no way to save a username in a session configuration, that there is no way to avoid being prompted for the username every time you double-click the session name. Not so – it’s just hidden in a less than obvious place:
To save the username, enter it in the Auto-login username box on the Connection → Data panel.
Silly? You tell me.
PuTTY identifies as xterm by default. If you use a UTF-8 locale on your Linux/UNIX machines, many applications will react to TERM=xterm by sending line drawing characters as a pair of characters consisting of a mode-switching character followed by some normal character such as x, q, and the like. PuTTY ignores the mode-switching character. As a result, trees, lines, boxes and the like don’t look anything like trees, lines or boxes.