Very common, my off side lamp is like a sauna! Put 'condensation' or 'headlight' into the search function and Im sure you will get all the info you could wish for.
Brilliant! I love a comedian! At the risk of thread swerve - this has reminded me of 2 true stories, probably not uncommon but here goes:
1. The apprentice at a garage told to check for leaks in a car using a hose. Gaffer goes to check on the work to find the newbie sitting watching the car, as a hose is wedged in the side window filling the car with water
2. Lad at a hotel is sent out to defrost the guests cars in the morning. Several broken windscreens later he realises pouring boiling water from a kettle onto the cars is maybe a dumb thing to do.