A cautionary tale...

...or two.
Alt title "How to set back dinner".
Imagine the above, without the black marks, which I've just added.
At a casual glance, the other end could, just as easily, be read to indicate 200˚C. It did :¬((...
Consequence:- all the veggies were about half done when I checked the I.R. oven only to find it was set at 75˚C. AAaaaaargh!!!!
Or, if you prefer, BUGGER!

Next.
We come to the case of the Onduline©.
Shed = 12': 4yds, you'd say.
Onduline sheet = 1 mtr. AHA! 3'+3" overlap, sorted, 4 sheets'll cover it. WRONG, silly bugger totally forgot it's a 3" overlap at each end.:¬((
Consequence:- One more sheet rqd. To replace the one I had to sever longitudinally to cover the last foot. Never mind EH? At least the shed won't leak, since, unlike one example I heard of recently, I inserted the nails at the crests of the wriggles and not in all the troughs, as a so-called professional is reported to have done recently.

One thing I'll say for T.W. RELPH.
A) He was both amused, and happy, to
"Repeat after me, "One of us is a Pillock" ".
and
B) To order the single, extra, sheet we needed.