Last Day of School
The event/issue is the last day of school.
There are no real people in his cartoon.
The people represent teachers. The school bus represents students leaving on the last day of school.
The cartoonist's opinion is that teachers are happy on the last day of school, because they no longer have to deal with students.
While not all teachers are this way (a lot of it depends on the students,) for the most part I agree with the cartoonist, because teachers no longer have to put up with obnoxious students, and they don't have to work for much longer after the last day of school.