my mom always did this. never made a difference to me, i would just look at the clock and my brain would automatically subtract 10 minutes from what was displayed.
Ditto about my mom and ditto about my brain. My clocks are usually set to the correct time. "A man with two watches never knows what time it is."
This makes total sense if your a "snooze button" person. I like to do the same on days I work early in the morning, its a pre-snooze wake up
I set the time to the actual time, but I do understand why people do this. Logically, it does make sense.