i took an uber at 2AM last month and was so tired i accidentally sat in the front. he seemed to think it was super awkward, so i tipped him pretty good.
and then for some reason uber charged me for the tip, but cancelled the main trip charge of 50$. it's bizarre - in the app it shows i paid him, but in paypal it shows they charged me, then uber cancelled it. i never hit cancel in the app though, the app still says i paid for the trip.
i felt bad but didn't know what to do, so i didn't get ahold of them. he probably gave me a 1 star and i'll never be able to get an uber ride ever again.