Paypal.
I paid my invoice for a group buy, but accidentally kept the default payment method, which is a bank account with no money in it. Dinged with a $30 fee. Now it's going to try again tomorrow and there's nothing I can do to stop it, and no way to get money into the account in time. So I'm going to get another fee, which will clear out all the money in that account. ****.
And why did I accidentally use the wrong account? Because there's no way to change your default payment method (or if there is, they're really good at hiding it). You can change your default payment method for "in-store" payments (who uses Paypal in stores anyway?), but I have not yet found a way to change it for paying invoices online. What a bunch of crap.
I called them and the guy said "sorry, we *have* to let it try twice before we give up". What the hell? I'm telling you right now to *not* try it! Just stop it! Ugh. $60 bucks gone for nothing.