I dumped my first customer today.
Backstory: We make custom collars/harnesses/etc. Key word here is custom. As in not pulled of the shelf cause they are already made.
Customer makes an order and sends me an email 24 hours later asking for when her item will ship. I explain to her that her item is custom, thus not in stock, and has to be made to order and that it will take about 10 days. 3 days later, she emails again, asking if it has shipped. I didn't have the chance to check my email that day (forgive me, I have my day job also, and generally 24 hours doesn't matter that much).
And she calls. Twice in the span of 30 minutes. The first to ask when her order will ship. The second to tell me that she will be filing a credit card dispute if her order isn't shipped in two more days.
So I refunded her purchase and told her to have a good day.