I protest that the problem isn't Chaotic Neutral as a valid character choice so much as CN is the primary choice of alignment for people who want to be Chaotic Evil, but don't want to write 'evil' on their character sheet. Likewise, the problem is not so much playing a character whose motivations may contrast with the bulk of the party, as it is not having the maturity to play those characters as anything but one dimensional caricatures.
I do think there are two to three other groups of people jostling to take up the Chaotic Neutral alignment--on the whole it's rather a busy place (which is why it comes up so often):
"Mischievous Rascals" - I see these people as coming at it from the opposite direction that the "I (perhaps unknowingly) want to write 'Evil' but can't because that's a no-no" group. Labelling yourself as "Good" makes it sound like there are too many strings attached--this person wants to have some self-interested fun now and then. Expect playful pranks (but rarely/never ones that would be permanently hurtful), nicking non-essential shiny things for personal enjoyment or to sell off later, and a sassy attitude toward anyone in an "official" position of power (unless, as with most Chaotic alignments, that official has personally earned the Mischievous Rascal's respect). These will be generally easy to deal with, because as long as they can crack some jokes and have a good time, they're up for basically anything, though a crackdown on dissent or dispassionately carrying out punishment regardless of whether it is "deserved" will probably rub them the wrong way.
"Actually Chaotic Neutral!" - The rare few who are more like, say, Garret from the original Thief series. He's really not an especially "good" person, and with rare exceptions he really is in it for himself. Even his efforts to save the city are easily attributed to avenging wrongs done to him or those he immediately cares about, or trying to prevent apocalypse (which is terribly bad for business). This kind of person is amoral (not immoral) and motivated primarily by "looking out for number one." First, survival; second, a comfortable living; third, excitement and entertainment. Ironically, this person is actually much
easier to deal with than the previous one. In general, their motivations will be pretty clearly stated, and often merely the promise of excitement, adventure, and
really shiny money is enough to get them motivated; they're also very rarely cruel, because it's stupid to make unnecessary enemies, and because having
that kind of reputation is bad for business. Those that do engage in violence--e.g. bounty hunters, rather than thieves--will tend to preserve that professionalism, and either way, a job's a job, though their methods for completing it may be...unorthodox.
"Maximum Badass" - This is the one that's sort of half-there. Unlike the "I want no strings" of MR, MB is about wanting nothing to "tarnish" your tough-guy reputation. This is the kind of thing Han Solo would do; he's carefully constructed an image of himself as a thoroughly "moral grey area" character, but when push comes to shove, he's really just "white that's got grubby" (as Granny Weatherwax would put it). In a sense, they're sort of midway between the above two; they see themselves as the 'not especially good person' but are easily convinced to go along with Team Good. While they might not turn down a secret theft, in a "character is what you are in the dark" moment, they'll do the good/noble thing before doing the amoral-self-interest thing.
When you add in the people who (knowingly or not) really want to play CE but can't, that's four fairly distinct (or three distinct plus a meaningful midpoint) archetypes all bundled into the same alignment square. I'm not sure there are nearly as many nicely-distinct variations for most other squares, and pretty dang sure they won't be as
popular as the four above.
Really, though, I'm more surprised that the majority of the group is Lawful; the vast majority of people I've played with favor either CN (usually not the "I reeeeaaally want to be Evil!" version) or CG, and see Lawful anything as a fuddy-duddy stick-in-the-mud.
