It could be a software issue, like a buggy update or a conflicting app. Or, it might be a hardware problem, such as a loose connection or a failing battery. Either way, it's like your phone is saying, "Hey, I'm not feeling well, so I'll just restart myself... again and again and again."
But here's the thing: rebooting can sometimes fix the issue! It's like a digital reboot therapy, where your phone gets a fresh start and hopes that the problem will magically disappear. And, sometimes, it works like a charm - but not always, unfortunately.