well it's harldy hard to maintain a bank account, so you don't get charged in the first place
Pretty ignorant statement.
I'm a home owner and have maybe 10-11 direct debits coming out per month, not all of which come out on the same day. I have 3 streams of income, all of which come in on different days. On top of this I have to account for my living expenses etc on a day-to-day basis. I am constantly checking my account in line with DDs, payments made on cards, cheques to ensure that there isn't conflict but unfortunately sometimes it just doesn't work that way.
Ever had the situation before where you pop to the local shop, pay on card and then the shop doesn't actually charge your account for two odd weeks? A few of my locals are notorious for doing this. It's all very well in theory to remember every single expense coming from your account but it's too easy to forget and assume your current balance is correct. We do have lives to live too.
We live in a world where there are delays and mistakes in money transactions on a regular basis. Banks rely on this, it's how they make their money. It doesn't make Joe Average in the wrong for not keeping on top of every penny in the matrix called our financial system. We didn't always have this problem, yet we've always been human... so you work it out.