The rules of business etiquette are very similar to the rules of social etiquette.
But there is a difference between the two sets of manners.
In the social sphere, the assumption is that you and your associates are equals, with some allowances made for age and sex.
The business world, on the other hand, is a hierarchy. Whether you work at a traditional, highly-stratified corporation, or a modern and casual upstart, whether the hierarchy is spelled out, or entirely unspoken, one exists. Just step on some toes and see what happens. Business etiquette dictates that employees defer to employers, sellers defer to buyers, and seekers defer to sought-afters.