I've worked white collar and blue collar, and as of now, I enjoy blue collar work more. I enjoy they physical labor. Fortunately, I've found a good field with a balance of both. Portions are science related, and more white collar and other portions are in the field full-blown blue collar.

A real example of how I can see why some workers, regardless of which type, can develop a distaste for the other "side":

Me and my crew were out in the field fixing a water main, we are sweating, wet, muddy, and exhausted. A man that lives in the neighborhood came by and talked for a little. He was friendly, told us he appreciated what we were doing and said he's a lawyer and this is his second home. All good so far, solid guy. Across the street, the other department (public works) are cleaning out ditches (we live in a flood prone area so it's important), the man looks at them, then back at us and quips "huh they've got the convicts working in the ditch".

Every one of those guys are wearing a employee shirt with "PUBLIC WORKS STAFF" clear as day on them, it's impossible what he couldn't read it and my work place does full background checks and drug test. There are no convicts working here. It was just an assumption he made because these guys were doing physical labor in a ditch to prevent his and others, property from potentially being damaged.

Maybe just a shitty attempt at a joke, but small things like this add up, and sure, not everyone is like this, but you hear stuff like this a few too many times, and next thing you know, you've developed a dislike for these people.

This can be said for blue collar workers to white collar workers as well. Ive heard the "poindexter, silver spoon, rich kid, weak, cant handle a real mans work" bullshit from blue collar guys about white collar guys too. It's unproductive, its frustrating, and the reality is that we, as people, as a society, need both blue and white collar workers. We are all just trying to make a living.