Carrying lights into or out of a set can be tricky - a light on a stand is about five feet tall and the whole contraption must be balanced on the shoulder as it's carried through tight quarters packed with people (some of whom heed the call of "hot points" or "watch your back", some who don't).
The solution (for me, anyways), is to keep the stand closer to vertical - it makes it easier to go around turns without knocking out someone's teeth, but means that I'm carrying 4 feet of steel above my head.
Every now and then, some joker of a set designer will put a ceiling in a set*. This is just mean. It means we can't light from above the set, the sound guy can't put the boom mic over the set, and it means that the four feet of steel I'm carrying is suddenly a HUGE problem.
Today (yesterday, actually as it's after midnight), as I was doing the 'get me into the hallway' limbo, I broke a VERY expensive light fixture, that was hanging from the low ceiling in the kitchen (I'm guessing the fixture was probably 8 feet from the ground).
For the rest of the day, the set dressers (who thankfully didn't sell me out when the AD stormed into set demanding to know who the hell broke the fixture) teased me like crazy. Every time I'd come into the set with a light, one of them would say something like "Look out - there's glass!" or "Watch out behind you!".
We were in the same set all day - plus we had a stunt**, so all day, the single remaining kitchen lighting fixture hung from the ceiling; a reminder for the set dressers to keep razzing me.
*Or fill the set with expensive furniture - most furniture on set is really cheap crap, because they know it's going to get fucked up, and the camera really can't tell the difference between something pricey and Ikea that's been painted to look expensive.
**There are stunts and then there are Stunts. Although yesterday's stunt was probably more of a pratfall (actor loses consciousness, falls over humorously), anytime an actor does anything that could result in an injury, it's called a stunt, and must have a stunt guy, crash pads, medic, etc...