My only regret is locking my keys inside the house the other day

Life is a funny thing, isn't it?
I've always been of the opinion that everything happens for a reason. I've made some mistakes in my past, but as a general rule I've learnt from them and become a better person.
I think mistakes are character building. A mate of mine was telling me tonight about his biggest regret in life. He grew up in the UK and his dad died when he was at college at the age of 20.
He basically couldn't deal with everything that was going on at the time and bailed to Australia for a year.
He said his biggest regret was leaving the rest of his family behind to deal with it while he ran.
I don't do regret. It's not healthy. Everyone makes mistakes in their lives. Everyone has a few things they might have done differently at the time. But those things make us who we are today. I wouldn't be the person I am now if I hadn't stuffed up a few times and wanted to do a few things differently.
But there's no point worrying about things that have happened in the past. There really is nothing you can do to change it.