My son had his own personal DI. Second week of boot, he gets caught smirking and is put on fire watch "every night until you graduate." Surely he was kidding......nope. Every week the letters home were more and more delirious because he was so tired. He missed expert because he fell asleep in the prone string (then made it every time thereafter). At the EGA ceremony, the DI told him did that to him because he wanted him to be ready to go to MARSOC selection. BTW his package was accepted, but since he was close to deploying, his BC would not let him go. Twice. One of the reasons he got out.

Another funny story is his personal DI tormentor had a little brother that was on the Island. After his platoon's Crucible and they were Marines, he saw his little brother in the chow line and ITed him in the pit for the company's entertainment.