If you feel like you must reach out and touch someone, please do. Except for the period between, say, 11:00 p.m. and 7:00 a.m. Call it the graveyard shift, or the dead zone for personal phone calls. There are two reasons for this voluntary blackout period: (1) Many people are asleep and don't require an ill-timed wake-up call, and (2) it's likely you are tired or drunk or both and are going to dial (or punch) incorrectly—several times. You may even become belligerent (yes, I've heard this happen) when the poor, sleepy, working soul at the other end of the line makes the mistake of not being the person you think you called, but didn't.
To the person who punched my number at 12:04 a.m.: It was clearly a wrong number the first time. Was it quite necessary to call two more times to hear my answering message and to be satisfied?