While I was at the Uni, we got a call from one of the research labs one day, saying that they were having trouble swapping a gas regulator across to a new CO
2 cylinder, so could we give them a hand.
Yeah OK, so picked up our shifter & headed across.
To make sure I'm doing the right thing (after all, it's in a research lab), read all the posted instructions before doing anything: cylinder tap turned off - yep; gauge showing zero pressure - yep; gas turned off at machine (incubator?) - yep; line disconnected there - yep; OK, remove regulator by unscrewing nut anti-clockwise - Jeez, that's tight, I can see why you've been having trouble, but OK, there she goes...& 3 bright, intelligent young researchers, the future brains & leaders of our Country

, all, in one breath, went "Ohhh, that's right, anti-clockwise is
that way"!

(& they'd been there for several years & had changed literally 100s, if not 1000's of cylinders over

).
Shook my head over that one & put the reg on the new cylinder, spun the nut closed, snicked it up with the shifter & thought that it wasn't as far home as previously. Asked them if that looked right & they said Yep, that's normal, we've been trying to swap the reg across since yesterday & turned it another full turn clockwise before giving up
