After a recent bad experience at work, were I was hung up on numerous times, I was left wondering about proper phone etiquette after dialing a wrong number.

I was raised to have manners, so even when I accidentally dial a wrong number, I almost always apologize kindly by saying something along the lines of:

I'm sorry. I must have dialed the wrong number.

Now I can surely understand hanging up if the person on the other line hasn't picked up before you realize your folly, but if you audibly hear them answer, I think it's rude to just hang up. This is further inferred when you realize in this digital day and age, your number normally shows up on the other end, whether it's a cell or stationary telephone (yes, some people, frequently office workers, still have regular phones).

So the question is: