I was on a flight a few months back where I wished the Y economy blinds were locked! :-)

"night-time" flight in source time-zone with full daylight outside, cabin lights off and all blinds closed. Some lovely small child was enjoying a continuous series of opening and closing the blinds, not only sending the entire cabin from daylight to darkness repeatedly.. but a super bright glare right into my eyes as I was on the opposite side of the cabin.

Fortunately I'm not a bitter old soul, and they only did it for a minute or two.. so was vaguely amused and carried on with my life.. until they repeated it a few hours later anyway ha ha.