That turn of phrase 'arse over tit' makes much more sense than 'head over heels'.
Other common english phrases that make no sense include 'cheap at half the price' (meaning 'very cheap') and 'you can't have your cake and eat it'. You blatently can, that's what cakes are for.
/tangent
( ,
Sat 17 Jul 2004, 1:43,
archived)
/tangent
"You can't have your cake and eat it"
means you can't keep the cake _and_ eat it.
/pedant
( ,
Sat 17 Jul 2004, 1:53,
archived)
/pedant