Does going quickly in and out of a stock really work? Won't the specialist or market maker get pissed off at you? If so, what can they do? What are the other risks? Please don't explain risks of investing or anything of that sort…I just specifically want to know whether this technique is useful and profitable.
Yeah that's what most day traders do. In fact I think the day trader mantra is "close all positions before the market closes."
I don't think anybody gets pissed off because you day trade. In fact one of the popular day trading strategies is to look for a certain "signal" shortly after the market opens, and be in and out of a stock within 1-2 hours.