My worst one was with a bloke who wanted to take me out for dinner (his treat, very generous offer I thought) and then took me to Garfunkels. don't know if it's even still in existence, but it was like an early version of an all you can eat buffet in a brightly lit canteen sort of atmosphere - only one up from a McDonalds really. 'Fair enough, don't judge yet,' I thought. Then the waitress came to take our order for drinks and he asked for a Coke. And this was the conversation that ensued:
Her: 'large or small coke?'
Him: 'How much is the large?'
Her: 'x pence' (or whatever it was then)
Him: 'Erm...and how big is it?'
Her: 'It's about this big'
Him: 'And how much is the small?'
Her: 'It's y pence'
Him: 'And how big is that?'
Her: 'It's about this big'
Him: (thinking for what seemed like an eternity) 'I'll just have the small then.'
Then he counted out the money for the bill to the very penny in cash, with all of his coins sorted out on the table. It's not that it was an awful thing to do, it was just the most uncool date behaviour EVEEER.