I don't really believe in teamwork. Do your job, be able to do the job of the guy next to you, don't sabotage anyone, and usually your company can excel. It shouldn't matter if the guy down the hall from you slept with your wife. You are not at work to bury hatchets, burn bridges, form friendships. Those are all by-products of being social creatures. The primary reason most of us go to work is the food, clothing, and shelter it provides.
What I'm really trying to say is your work is your work and your friends are your friends, and they don't have to mix. You should be able to walk away from work and leave it there. When you leave the thresh-hold of work, have home just be at home, not stressing about how you dislike people at work or how the lazy ones are affecting your productivity, because if it is, they now have you working off the clock for free. No job is worth working for free unless it's a volunteer basis. You're paid to do a job and do it well, you don't have to actually care about the job.
Some organizations have sports days where everyone is expected to attend, the wife and kids are invited, and everyone is supposed to hang out. What if I don't like 95% of the people I work with? I now have to smile and act friendly with people who I would never talk to outside of work. Then if they think you are a nice person (which I am not, I just have manners. It sometimes gets mistaken for friendliness), they want to see you outside of work. Work now is forcing itself upon my mental health by intruding on my familial solitude.
I don't want my kid hanging out with your maladjusted, remedial child. He/she is cute, I won't argue that, but it's not the influence I want for my kid. You're gossipy wife is going to cause me more harm than good because all the back-biting and rumors will now trot through my home. The lines will begin to blur and I'll never be able to escape or get a moment to myself because work will now be everywhere I go.
To quote Fight Club: "You are not your job, or how much money you have in the bank!"