This Angry Parent thing

I've never really wondered what our parents were thinking in their heads when and after they scolded us until I started getting agry at nate.
There are two different approaches, i've learnt.
1. Is you get angry but it's more of a "pretend to be stern and upset" and leave him to worry about you being angry for a while, so that he will understand the serverity of his mistake. So actually, you're not really angry and just thinking of what you're gonna have for lunch later on. - you kinda get what i mean right?
2. Is that he makes you So mad that you are actually angry and wondering what you did wrong and start to feel guilty about not being a good parent which then led him to make his mistakes.

I've been recently feeling more of the second option..
I dunno. Perhaps, nate's getting more stubborn or maybe i've been getting more impatient.
I honestly try most times.

Today, we were supposed to leave the house for school.
Nate started to throw tantrums because he wanted to stay home and play with his toys.
I kept my cool and called him.
Once
Twice
Thrice
To no avail.. so i offer him the option to take along his toys, he shouts "NO!" and starts to cry.
Asking for his grandmother. So ok. I tell him get grandma to put him in the car. As we're putting on his shoes, he decides to throw his cast iron train model (Arthur) at me. It hits my shoulder and then the floor. This was not a playful throw. It was an anger infused action.
First thing i did was to beat his hand.
Maybe it was a bit too much beating from my end.. and i realised that that was my first reaction.
Sigh.
Then on the way to school, all I could think about was how bad a parent I was.. and i started to question if i was being too harsh. (But i gave him options and i asked him nicely so many times to get a move on.)
Viscious cycle we have here.
I so need help.
Isn't there some kind of manual that comes with this whole parenting thing?