Atleast you did manage something.
In my case, I was at subway, as most of people here know that there's a special deal on Sunday of Subway that buy 2 drinks and get a 6 inch sandwich free. Actually I didn't read that 2 drinks thing and made an order of 8 sandwiches and got them packed. Went to the counter and the guy said "sir konsi drinks" I said "nae koi nae(As it's expensive there :P) Counter guy replied "sir apko 16 drinks leni paregi warna aap 8 sandwiches ka bill de" XD and he told me about that 2 drinks deal. I just made an excuse ka "arey wallet gaari ma reh gya ma ata hoo lakar"(There were lots of people in that branch that day, especially girls :() then I sat in the car and got out of that place like a crazy maniac trying to save his a$* from Police! XD
Never went to that branch again!!