There are some spam issues in the comments, so I had to disable comment editing for a short time. It'll be back once the spam bots are gone. FYI... they leave a comment with "great" and then edit in the spam stuff later, to get around the filter.
(Comes from an old root that was about laughing and that we can find in Latin and old Slavic. Might be an immitation of "haha" and "hihi" as onomatopoeia.)