I’m Jack, and early school was pretty brutal.
Beanstalk, Sprat, Skellington, & Jill etc. Probably didn’t help that my mum’s name is Jill.
When I was 8 I was on holiday in Majorca and the holiday rep (a grown man) called me Jackass and the other the kids called me that for the rest of the holiday 
Nowadays I get a lot of folks saying ‘hi Jack’ and then falling over themselves laughing because they said ‘hijack’ 