I am one of those guys who never mastered a manual. Furthermore, the traffic in my city is so congested. You are constantly changing gears. However, my lack of experience almost caused a problem once.
I was helping to move my mother-in-law into a retirement community. A lady came up and asked if I could help. She had put the emergency break (the kind with the lever between the front bucket seats) but had it stuck and could not get it to release. "My husband will kill me if he has to come out here." I doubted that, but in the interest of domestic harmony, I said I would help. I knew the trick was to get it to go up one more notch while holding the release button. In a matter of seconds, the brake was released and the car was rolling backwards. Not noticing that it was a manual when I got in, I hit what I thought was the break pedal. The lady strongly urged me to use the other pedal. I was pushing in on the clutch. I stopped the car. Put the emergency break in a less severe position and got out. The person observed that I must not drive a standard much. I said it has been about 20 years.
As I stepped out of the car, I noticed that it was a Jag. I had a better understanding of her concerns about the car rolling back into the driveway portion of the parking lot.
I will know in the future to look at the pedals when I get in a car to make certain it is an automatic or standard.