I've got a blister like a gun turret.
Rule 1: Don't run polypropylene cord through your hands without wearing gloves.
It looks smooth as liquorice, but if you examined it through a microscope I bet it would be like an uncut hedge, all ragged and vindictive. You could probably use it for making musically functional prosthetic legs for grasshoppers.
While we are about it, here are - in no particular order - a few more hard-won tips from Uncle Toby:
Rule 2: Don't take your boots off to test if an electric fence is working.
Rule 3: When eating spaghetti, make sure the plate is fully on the table.
Rule 4: Do not drape a coat with velcro fastenings over a chair when there are women in stockings around.
Rule 5: The puddle-jumper ahead driving at a brain-numbing four miles an hour is going to the same party as you; do not hoot or gesticulate triumphantly as you finally overtake.
More anon probably, if they occur to me.