Practice heavy-handed office politics and you'll be ostracized. At others, it's vicious. Just how you play office politics is, at the bottom line, a moral choice. We all must live with ourselves. Politics really is simply a practical way of reaching compromises that satisfy most of the participants.
Most people run afoul of office politics when they forget that.
They try to push proposals that benefit themselves or their part of the company without first quietly identifying objections from others and attempting to mollify them in advance. By identifying objections before you act and bringing possible objectors into the loop, you can go a long way toward getting the sand out of the gearbox before the wheels start to grind. Everyone needs a favor now and then. If you're prepared to provide it, you can expect a favor in return. That doesn't mean you should be the office patsy.