Another hunch that I have is that as you get older you tend to have less unique experiences. I believe our brains compress the information and an entire day that was much like the previous day can just feel like it sped by quickly. Alternatively, if you go on vacation or change your routine then time will slow down as you process a lot of new information.
You see 2-5 elections per year.
The day lasts from 0500-2130h (at least here in NY)
New faces throughout the day.
Constant stimulation, followed by periods of inactivity.
Practically impossible to guess when someone will walk in the door.
Strict rules for how you’re supposed to conduct the election, combined with the anxiety of how your co-workers and yourself actually perform.
And then waiting for the results.