Couldn't agree more about people who get upset because they're still at work at the end of a shift. But the fact is, more on afternoons than mornings, that you just don't need as many people towards the end as during the rest of the shift.
This, however, leads to it's own problem, primarily due to bean counters.
If you need, say, 24 ATCOs plugged in working at tea time rush, plus enough more to give them breaks, say 7 more, giving 31 total, but only 10 in total for the last hour of the shift, what is the point of keeping the other 21 sitting around?
The trouble is you cannot just bring people in for the busy periods, although some of the spins are leaning that way. The busy periods are annoying beasts and keep moving depending on weather, days of the week, time of year, events earlier in the day etc..
What a great invention an emergency pop up ATCO kept in the cupboard would be...