the kid that's hard to love

please somebody tell me that I'm not alone here. I love my kids completely, they are amazing. but that little one of mine is the MASTER of pushing my buttons and honestly, sometimes it's a real struggle to keep it together! have you ever had someone in your life who seemed to bring out the worst in you? every mean thing you could think of to say, every uncharitable thought or sarcastic, short-fused reaction that occurs to you will undoubtedly come out around this person. doug r. was that person for me in high school. I am still ashamed at some of the things I said to that poor kid for no reason at all. and I fear that my lukey will be another of those people if I let my guard down. he seems to bring out the worst of my parenting far too often.
granted, I fully acknowledge that I have some issues of my own. it does not take much to make me angry, and I allow quite a few insignificant things to effect me negatively. but holy crap! this is a kid who does. not. listen. almost every attempt at discipline is met with laughter, an increase in the behavior, or is just plain ignored. consequently, most of my time with him seems to be him terrorizing everyone and me trying very hard not to be clenched up just waiting for the next thing he does that will drive me nuts.
diaper changes: 90% of the time I have to pin him to the ground with my left leg while he lays perpendicular to my body and I keep a death grip on the ankles of his kicking (hard!) legs so that I can do my thing, all while he laughs like a loon or is otherwise screaming because he can't do whatever he wants to do. I am terrified that by my trying to hold him down so that I can change or dress him without him flailing in his own poop or running away I will accidentally leave a mark on his body and the daycare will call social services on me or something. sometimes it seems like EVERYTHING with him is this complicated. when we're all in the kitchen and I'm trying to get food ready or clean and he has to be up my butt or hanging on to my pants yanking them down, etc. meals are always stressful because he throws food, upturns his drink to play in it, or the new one is to use his waffle like a Kleenex, then rub the whole snotty/waffle/peanut butter mess in his hair before generously offering it to or throwing it at me with the gleeful exclamation of "eeewww! yucky!!".
I don't know, I'm sure I'm over-dramatizing it. he's really been getting to me lately and I'm starting to feel like it will always be this hard even though I know that's not true. on the flip side of all the craziness, he really is a sweet boy. he loves his brother and the dogs and is really talking up a storm. he likes to play games and wrestle and I swear that his smile is the source of all sunshine. he's just a tornado. a beautiful and devastating tornado to all things calm. I'm terrified to see what kind of teenager he will be. in the meantime, i'll just continue to do the best I can to avoid getting myself sent to prison and ride it out! but any words of wisdom for dealing with difficult kids would be greatly appreciated.