Now, this is a somewhat different issue, and one that's easier to answer IMO.
I'm sick to death of stock D&D settings. I really, really am. Our Darksun campaign, our Dragonlance campaign and now our Forgotten Realms campaign are only different in window dressing. The characters, by and large, could be imported from setting to setting without any real change. Sure, the flavour of those characters would change, since some of them are very embedded in a specific setting, but, from a higher POV, yeah, there's absolutely no problem shifting one character from setting to setting.
And, as I said, I'm absolutely sick of it. I've been gaming in kitchen sink settings for far too long. I want a setting where the setting actually matters, where you can't simply plop down Wizard #23 into the game and nothing changes.
So, no, it's not, "Hobbits simply don't go on adventures", it's, "This is a world where hobbits have all been wiped off the face of the planet by zombie squirrels." Don't bring your gnome priest of Garl Glittergold into my Darksun campaign please. Make a character that actually FITS with the setting, rather than playing against the setting for the fifteenth time.
Every single group I've ever played in, including the current one, I see the same thing. DM sets a setting, whatever that setting is, and you get four players who make characters that are either embedded in the setting or are at worst neutral to the setting (yet another Man with No Name, fish out of water character), and then there's always that one guy (who is, admittedly, sometimes me
) whose character isn't just neutral to the setting but is actually openly hostile, in that it runs either directly counter to the setting, or is badly, badly out of sync with the feel of the setting (playing a psychotic murder hobo in a Dragonlance campaign as a recent example).
Look, I'm not against intra-party conflict. That's fine and great. But, that conflict shouldn't be so fundamental to the character that it just stands out so badly that it has to be lampshaded session after session. The Shardmind in Darksun - yeah, you look like a walking diamond, but, we'll ignore that by throwing a cloak over you so that you aren't instantly murdered in the street. The kobold bard that is suave and good natured and acts in every way like a gnome, but, is a kobold and the player expects to be treated well and get along with everyone the party meets.
I'm frankly just sick to death of players that feel that playing the "anti-setting character" somehow makes them interesting and unique. It's the lazy way out. I mentioned this upthread - it's easy to stand out when you play a Cylon in a Star Wars campaign, but, that doesn't make it interesting. It's an old and tired cliche that I'm just really tired of. Make a character that fits with the tone and background of the setting, make that character with ties to that setting, and THEN make your character unique and interesting. That's the challenge.