A colleague decided to save time by not washing the chemical tub out yesterday. I had to take this 30 litre drum out of the bin he'd stuffed it in, and in the process I got a splash in the face. I was not amused, especially as he had left early on his shift.
When he came in to take over from me I told him I wasn't amused. Apparently it was my fault for not swapping the tubs over the previous day. He argued the point for quite a while.

I eventually thought "I've reasoned enough here. Time to be honest."
So I waited for him to finish, and said "Shut the fuck up, you should have cleaned it out, and next time I'll grass you up. It's simple. Any more risks with my safety and I'll make sure you get well and truly fucked up. Got it?"

I think he did.

I then handed over as nice as pie and left for the weekend.