One Easter I went to a small chapel seating perhaps 50 people, and the first half dozen rows were all occupied by nuns. I'm not sure what happened exactly, but the censer was emitting great clouds and within about five minutes the entire church was full such a thick fog that it is no exaggeration to say the altar was not visible. The best guide for where the front of the church was came from the discreet coughing of the nuns [who were not sure that was strictly allowed] and everyone was in two minds whether things were sufficiently bad that the service should be completely abandoned or to carry on regardless. For those who are not familiar with it, church incense comes from something a little like small lumps of glowing charcoal; once it is lit it is not easy to put it out without water or a fire extinguisher neither of which was readily to hand. Or if they were, no-one could find them in the smog.

Natually, we carried on and eventually left the service vaguely resembling kippers.