I have a 3 year old son. For quite a while now he's been testing his limits to see where they exist. It's one of the ways kids learn.
My wife and I apparently have different ideas about discipline. She feels guilty if she barks out a command or discipline in a strong voice or spanking, no matter how mildly. Obviously the kid exaggerates it to high hell, any time he's being disciplined in any way shape or form, and he found that his pouting and crying fits are just the way to keep mommy from attempting any sort of discipline at all, ever. In fact, he has taken that approach one step further and does it to get whatever he wants, any time he wants from her. I feel bad for her, actually, because he's like that almost all the time around her and it's been that way for almost a year. It would truly make me miserable as a parent to be around a (faking) miserable kid constantly. But, I guess she doesn't have to feel guilty -- just keep shoving more candy and toys in his face until the next episode in 5 minutes.
I, on the other hand, respect my son and show him that respect by recognizing the fact that he understands what's up. I give him the choice and he knows he has it. Kids aren't dumb. A couple times, way back, he ignored calm warnings that he would get a spanking if he kept doing what he was doing (deliberate really bad something). I proceeded to bend him over my knee and give him one firm clap on his butt. He barely felt it through his diaper, but he knew what it meant. After just a couple of those incidents, he realized I wasn't joking when I said "stop", now all I have to do is look at him the right way and he stops being bad. He absolutely never throws fits or gets whiny around me. In fact, he doesn't think about whininess or crying at all, so we spend most of our time together laughing and playing. He's a very happy little kiddo'. I wish my wife got to enjoy that side of him more often.
My son and I have a super close and strong friendship. But, he does respect me and knows without a doubt that I call the shots.
I don't believe in discipline, of any kind, out of anger. If a parent can't hold it together and their authority is clouded by personal anger, they need to leave the room and cool down before dealing with the situation. I grew up in a house where most of our discipline happened out of anger. Plenty of blood was spilled and serious bruises. We didn't get out of line much, but it was mostly out of fear rather than respect. We do still respect our parents though, and it's because of what they've done in life and for us, but not for the way they handled discipline. I must say, though, if there was no physical discipline at all, we'd probably have turned out to be way out on the wrong side of the tracks.