Yes! I sincerely regret hearing a gas leak when checking my experiment and turning up the pressure to try and find out where it was coming from. Turns out I had a blockage in one of my tubes, and turning up the pressure caused a large metal stopper to come off with an almightly bang. Luckily it didn’t travel very far.
I accidentally melted the inside of a furnace once when the thermocouple I was using to control the temperature short-circuited, resulting in thermal runaway! Fortunately it didn’t cause any damage beyond that. It taught me to always check equipment (at least) twice, especially when high temperatures, voltages or toxic chemicals are involved, before commencing an experiment.