Mommy613-
There are two very different types of pranks- harmless ones that cause no damage (hiding a piece of chalk in the eraser) and pranks that cause a loss (ordering pizza to a teacher in middle of the night).
The way Yeshivas are designed (for the most part) is to give the bochurim very little free time since the less time they have to be bored the better. There has to be some sort of outlet for them to release the energy that teen boys build up during the day.
There is no justification to pranks that cause damage.
Before I started teaching my father gave me some advice.
“Every Jewish boy belongs in yeshiva (although not every Jewish boy is necessarily in the correct yeshiva for him), not every Jewish man belongs in chinuch. As a teacher you have to be able to handle whatever pranks are aimed at you and not give punishments out of anger. If not, you do not belong in chinuch.
Just like a neurosurgeon, who has the life of his patients in his hands, can only perform an operation that is beneficial solely for the patient, how much more so a mechanech, who holds the future of his student and all future generations, can only give a punishment that is appropriate and beneficial.”
As a teacher I was definitely the subject of many pranks, the vast majority of those being harmless.
Seeing them score (as a whole) over the 90th percentile on standardized exams, and the relationship I still keep with some of them as they study for their professional exams makes it worth it in the long run.