I think I heard the most obtuse reason for being dismissed from a job: being asked not to come back because you put in your two weeks notice. I can understand this action if there was conflict. I can even understand it if quitting was a preemptive strike rather than being fired. But what I cannot understand is the blatant disregard for etiquette on the side of the employer, when the (former) employee help up their end of the bargain.
What this makes me wonder is, “Why should someone bother giving two weeks notice if they are going to lose their job on the spot?”