Roger Shoaf writes:

On a side note, when you were plastering your pool, why didn't you rig a
chute to pour the plaster down into a waiting receptacle rather than
bucketing it?

Running a liquid down a chute is equivalent to throwing it down; very
little kinetic energy is lost to any resistance. The chute may guide where
it arrives at the bottom, but it still arrives with about the same kinetic
energy, which is to say, splattering everywhere.

I'll admit my untried intuition on this was as wrong as yours. I tried it
and learned the hard way.

You should be skeptical of your own intuitive analysis of garage doors,
because it is also quite wrong. The system contains on the order of 1000s
ft-lbs of energy, and your suggestions for disassembly will result in an
uncontrolled release of that energy, one way or another, and many of those
ways are destructive or injurious. The only proper method for such repairs
is to first relax the torsion springs, absorbing the energy safely into
your muscles over a period of 30-odd quarter-turns of an 18-inch winding
bar.