I have noticed that I have a bad habit of looking at the time. Often. It's hard not to do so when you have a computer clock, a phone clock, a cell phone and a mirror (to see who's sneaking up behind me this time) with a clock.
And all of them say different times. The phone clock is phone time, the computer clock is server time, the cell phone I consider to be real time and the mirror clock I try to have set to time clock time. And they are anywhere from 2 minutes to 5 minutes different from each other. It gets difficult trying to do the math from one clock to another so I try to go by just my cell phone and the time clock. Yes, I know I could set my cell phone to the time clock but with how quickly it gains or loses time (depending on its moods) I'd be constantly changing that. Then I would be late or early all the time. That would drive me nuts.
I also have several alarms. I have my noon alarm for changing positions and my 4:25 alarm to remember to take my laptop home (in case I haven't used it) because if I'm not using it, I might forget I brought it in. Setting the 4:25 alarm is quite helpful because then I have no need to watch the clock.
If I didn't have to do math between the times I would just not have any other clocks visible and just go by the cell phone. Unfortunately, it doens't always work that way.