Substitute teachers like substituting on "minimum day". It cuts the school day by as much as 1.5 hours. Since we're paid per day rather than per hour, it's one of the few substitute teacher job perks. Same pay for a bit less work.
Conversely, some substitute teachers don't like half day assignments (...because it's half the daily pay). Personally, I don't mind half days as long as it's the second half. You don't have to get up early and usually the lunch period is included as part of the afternoon half of a school day.
Therefore a "perfect storm" for me in subbing is the afternoon, half day assignment on a minimum day. I haven't ever experienced one...until today!
My day started at 11:30am, went to lunch at 11:45am, in the classroom from 12:15pm to 01:15pm when school ended.
One and a half hours work for a half daily rate works out to better than $40/hr.