I presume this has been answered several times in isolated cases (or perhaps somewhere else on the main site?), so I apologize for the lack of resourcefulness. Alas, this is more related to day-to-day dealings with the people in your geographic location.
When you meet people who you perceive to be useless whom you would normally end up avoiding, but for one reason or another (curiosity, they are your friends' friend, etc.) end up getting the opportunity to talk to and accept this fate for a temporary time frame under the hope that this endeavor won't be entirely useless, you tend to think of methods to get rid of them or failing that, engaging them in topics that aren't inane. I had the misfortune to be invited to sit with these fellows the other day (two of whom I knew from the gym) and realized that I normally tell them I have prior obligations and thus cannot accept their offer before this even happens. But at the prospect that perhaps I was being too cynical with others, I thought I'd give them a chance and see them as individuals.
Of course, the probability was slim and they ended up conforming to the mold: trite babble about inside-jokes (which naturally made me feel left out) and entertainment (most of which I avoid) coupled with the exasperating attitude they had towards conversation: frankly, that topics and ideas should just be thrown out of their mouths as fast as possible, every opinion heard and their duration and significance minute. Because, life's a joke right? Topics of racism were brought up facetiously, but since everyone was oh-so-witty and sarcastic, nothing anyone said was taken seriously. They talked about both sluts and "damaged goods" rather fatalistically as if all women were like this and should be treated this way (and of course, life has no meaning so we should just use them as fuck-dolls). There was even a brief philosophical discussion, which to my expectations revealed their solipsistic/fatalistic/hedonistic tendencies. These fellows just loved to talk about nothing at all.
All the while I was trying to find something at least vaguely useful/interesting/engaging to break the trend of stupidity emanating from their direction. And I had nothing. Potentially fruitful conversations were cast aside in favor of Bruce Lee vs. Chuck Norris comparisons.
When you fellows find yourselves in such a situation, do you tend to make up an excuse to leave (having failed to do so initially) or do you act sincerely insincere and accepting of the conflict that will arise? If the latter, then how do you manage to indirectly engage others?