My mum and dad got engaged because they were mates and they were travelling to Devon together and called in on my dad's folks on the way.
My dad's dad assumed they were there to announce their engagement and he was so excited that they didn't want to disappoint him. The story goes that my dad rolled up a kitkat wrapper and moulded into a ring shape and my mum said.. 'Ok.. might as well...'
Lol. They've been extremely happily married for 35 years!