I'd repair a TV, people would pick them up then call an hour later "all I get is snow!". They thought all you do is plug it in to outlet, no antenna or cable.
One service call an old guy had the back off and a trouble light going saying "can I help? Need tools? Water? Another light?" on and on. Finally I said yes there's something you can do. He got all excited!

"See that chair over there?" "Yea-yea-yea...I see it!" he said.
"OK...have a seat". "Ok,ok,ok,ok...now what?"
"You see that lever?"..."yea,yea,yea,...I see it!"
"Ok...pull it!" I said as the foot rest flips up.
"Now what?now what?" He says all excited.
"When I say go, I want you to pull that lever again!"

So 20 minutes go by, I fix the TV as he pouts, fill out invoice and say "now pull the lever, I'm ready for a check".