Asking for money is totally awkward. Finding out who made that long distance phone call is impossible.
Life is way too hectic to remember.
When I reimburse someone, I never know what I'm actually paying for. It's annoying keeping track every time I pay for something for the house. Calculating every last household item is tedious. Getting everyone home at the same time to discuss bills is hopeless. The post-its, receipts, and scribbled notes scattered around the house are a big mess.