Here is an example of how it is done in the real world.
Let us imagine it is a pleasant day, the traffic was light, and when you arrive the customer says something like "Wow that was fast, I figured I would have time to get done weeding my garden." As you kneel on the stoop the soft padded carpet welcome mat cradles your knee and the lock cylinder is in the perfect position. The lock yields to your mastery with a few gentle probes of your instruments and you are in.
OR
It is three O'clock in the morning and it is raining and the wind is sending a chill through your wet clothes. You just drove through a construction zone that had traffic backed up for miles. The customer is on the third floor of an apartment building. He and his wife have been drinking, their baby is crying, and they are fighting. The lock is mounted on the left side of the door and is upside down. There is also a screen door without a hold open and it can't fully open anyway do to an obstruction that you can't move. As you kneel down your knee hits a nail that is sticking up and your pen light falls from your mouth, as you grab for the light, you drop one of your instruments and it ends up falling through the crack in the deck to the second floor landing and your penlight rolls off the porch to the gravel drive.
The fall kills the bulb in the penlight, and you spend 10 minutes looking for the spare bulb. Your supply of "magic words" you keep on hand for these circumstances is dwindling and as you trek to the third floor once again you forget about that stupid nail and of course kneel in the same damn spot.
You knee is bleeding, your pants are torn and now you realize you forgot to recover the tool from the second floor. It now takes you about 5 minutes to find the tool and get back into position. The baby is still crying, the customer and his wife are still screaming at each other and the damn screen door is still in the way. The stinking lock does not cooperate and just as the batteries in the penlight are on their last gasp the lock finally yields.
You twist the knob and the door comes to a stop because of the $2.95 made in Taiwan chain lock. Your customers finally notice and say "Oh no, we had the key to the knob, it was the chain lock key that we left on the counter."
Of course this yields right away and at first you are grateful to be invited inside until you realize that these folks have not changed their cat's litter box in a bout a month as they have you wait for a while the baby is changed and they search franticly for their wallet. They then ask, You do take ATM, right?
As you are forced to accept less than your full fee because the bank must have made a mistake you drop off the rum soaked customer and notice your missed call light is blinking on the cell phone. You call back your best commercial customer only to find out that they had just hired your competitor to repair their access control system that had been vandalized, and that job would have been inside and warm.
Is that enough Zen for you?