There is some really interesting stuff about ESTPs/ESFPs in this thread.
I'll drop my thoughts below:
(1) I'm a ESTP and am the life of any party I end up at, or start, and I never have fun at other people's expense. That would be socially ungraceful, and ESTPs are masters of socializing. One of my best frineds (15 years I've known him) is ESFP. He and I are VERY much alike. He is actually more prone to having fun at the expense of others.
(2) Jennifer is right, when ESTPs determine it necessary to "crush" someone in the process of executing something relevant, we are not concerned about sugar coating it, but that is business, not social behavior.
(3) ESFPs are more impulsive than ESTPs, and are more "moody." Everyone knows when my ESFP friend is in a bad mood, or a good one, and he oscillates between the two poles with an unpredictable regularity depending on whaty is going on in his life. I am very, very consistent, and cool/calm/collected in disposition, especially when a crisis comes. ESTPs have nerves of steel, and we don't get emotionally moody, even when we are pissed.
Of course there is alot of variation possible, even between two types as close to these, but my comments are not meant to speak for all, only to share my experience on this topic.
P.S. I'm getting tired of the "used car salesman" references. I'll sell shit to a farmer if I need to, but that's hardly an aura that is definitive of my persoanlity in any manner whatsoever. Believe it or not, most ESTPs are very well likied, and alot of people come to us for advice, because they know we have a cool head and will think through a problem to find an efficient solution to it. Used car salesman don't do that, and people don't go to the for advice.