I don't wake up to an alarm clock. No harsh buzzing or loud radio to wake me up. I have an alarm clock in my bedroom, but it's just there to keep the time--I haven't set the alarm in something like fifteen years or so.
I just wake up at some point in time. I have a regular 8 to 5 job, and I usually wake up about 6:30 in the morning. It's a habit. I don't remember exactly how I got started without the alarm clock, but I remember that at some point in the early 90's, I didn't have a job for about six months. An aunt had given me a somewhat large sum of money, and so I quit my job and slept in every day until the money started running low and I decided I needed to go back to work.
During this period of unemployment, I went to sleep when I felt like it, and woke up when I felt like it--I wasn't on any kind of schedule, except that the Perry Mason TV show came on a local UHF channel at 11:00 am, so I always made sure I was up in time for that.
But when I went back to work, I still didn't bother with the alarm clock--I didn't need it, and I haven't needed it since then. I try to make sure I get to bed early enough so that I get a decent amount of sleep, eight hours, or something close to that. When I went to bed, I would tell myself what time I wanted to wake up, and lo and behold, I would wake up at just about that time.
Over the years, this has become a habit, and I don't need to tell myself what time I want to wake up, unless I need to make a change to my regular schedule.
I must admit it's not perfect. I've occasionally overslept when I've stayed up way too late past my normal bedtime, or when I've been sick. Usually I "oversleep" by waking up first and then going back to sleep instead of getting up, rather than just sleeping through my normal wake-up time.
So does this really mean anything important, or is just one of my peculiarities? I don't know, but I imagine if I can do it, then many other people should be able to do it, too. It's a matter of habit, and of allowing yourself enough time to sleep, and of putting your subconsciousness to work by telling yourself when you want to wake up. It really is nicer to wake up to silence, instead of to a harsh buzzer or loud music. If you need something to smash in the morning, keep some empty aluminum cans or something handy.