The big deal in the UK, a few years ago, was that a person would go overdrawn, deposit money to cover it immediately but then get charged an overdraft fee by an overnight process. This fee would put them overdrawn, leaving them liable for a second overdraft fee - which would be charged the next night...

This was ruled to be illegal and banks had to set up whole departments to process return claims. I suspect this is the main cause of the big headwind.