How stupid can I get.

Not as stupid as my ex father-in-law! Years ago he dropped by to visit and when he went to leave his car wouldn't start. My 'ex' had previously told me her dad used to own a gas station so I didn't question him when he went to jump his battery off one of the dual batteries in my old '77 Ford (didn't know any better then - got a Ram 2500 V10 now) pickup.
Well, he hooked the cables up backwards. It sparked the hydrogen gas and blew the battery apart leaking battery acid down the inner fenders.
The clown said 'oops', connected the cables right to the other battery, started his car, then said 'thanks' and drove away leaving me with my jaw on the pavement. Never even offered to pay for the blown-up battery!
Oh well, he's gone now. Hope he's still searching for a jump-start wherever he ended up!