Wrote custom test-set software in a clean-room. Bunny suit, mask and rubber gloves for 8 hours a day. It was a windows box connected to a x-ray diffraction machine so I had to be in the room.
I used to catch myself surfing the web in the clean room after hours. "Wait!" I would say to myself, "I could be doing this outside the clean room, where I could take off this silly suit!"
But they are stressful places to work. The noise is quite troublesome and the ergonomics are generally awful.
There was a day when I was sitting there in an academic fab, in my bunny suit, and a fly flew by. At first I didn't notice. Then I did a hilarious double-take.
I believe the airlock design has been improved since then.