I am probably one of those people that keep cancelling appointments with friends. Nothing personal. I'm just busy (work, kids) or probably not organised well

I am probably one of those people that keep cancelling appointments with friends. Nothing personal. I'm just busy (work, kids) or probably not organised well enough. Some of my friends understand, some are worse than me, but some take it personally. Interestingly, there's no relation between the time I spend with a friend and how mad they are with me. Nobody should be hurt. It's my life, that's what it is, the day has only that many hours, things happen, and things will change one day. Right now, I don't even have time for myself.