I forgot to scan my one banana and after I realised it I came home. Do I go back? Will I get in trouble?

The internet police have already alerted the supermarket. They’re now liaising with CCTV to track all banana sales and are examining credit card transactions and loyalty cards to obtain your address. Traffic cameras are also being traced so that their revenue can be claimed back with no expense spared. Dude, stop being so paranoid and get on with your life. It’s not like you’re stealing something outright as there are other items in your basket. If you own up, it’s just going to cause more hassle and could just be wasting everyone's time; especially if the store decides to make an example of you. It'll cost them more in labour to sort out the mistake. If you’re really worried about it, buy an extra banana next time and give it to a homeless person, or at least leave it behind at the self-check-out the next time you visit. It’s karma. I’m sure there’ll be an instance (past or present) that you’ll be overcharged for something; whether it’s at a restaurant or for a special offer that didn’t get processed correctly. Mistakes happen, we're only human, it's allowed. Relax!