hmm, last time I checked, patting a kid on the butt isn't really abuse- I got spanked a few times in my day, but looking back, they didn't even really hurt- it was more the shame of it than anything else. And if you think missing a single meal for misbehavior is reprehensible, take a trip to Africa. I know that example is overused, but seriously- the kid could quite possibly use a few less calories anyway, if obesity is as big an epidemic as the media says. As for kicking your kid out of the car, my parents never did that to me, but at the same time my mom walked home by herself every day from elementary school through high school, without a key to get into the house, and she's not exactly running up therapy costs because of it. Be an adult and punish your children when they go astray. If you're a good parent, you'll know the difference between being a friend and being a parent.
I'm a teenager living in my parent's house, and I can honestly tell you I'm glad they spanked me and grounded me and chewed me out when I was younger, because it taught me not to give them a reason to punish me further on in life. I'm sick of parents who let their kids (my friends) do whatever they want because they're more concerned with being the child's friend than being their parent. Sure, you can be friends with your kids, but you still have to be an authority figure and prepare them for the real world, where they can't do whatever they want without repercussions. Be there to talk to them, laugh with them, and help them with problems, but also be there to slap their hands when the reach for the cookie jar out of turn. If you're a good parent, you'll know how to balance friendship and authority.
That being said, you obviously need to be responsible in your punishments. Spank your child, but don't beat the crap out of them with a wooden switch. Ground them from something they hold dear, but not from something they need- monitor computer use so it's only for homework, or limit their cell phone to family numbers and 911. Send them to bed without supper, but make them a decent breakfast the next day, and talk things over with them as they eat (this an especially good way to show you've forgiven them and make amends). Kick them out of the car on the way home from school, but not a long way from home. Don't take your anger out on them- you want to teach them, not torture them. If you're a good parent, you'll know the difference.