I think “panglossian” comes very close to what he wants. The base meaning is that whatever is, is best. It comes from the eponymous Dr. Pangloss in Voltaire’s Candide who believed that this is the best of all possible worlds.
It’s the opposite, or flip side, of the “grass is always greener on the other side of the fence” syndrome?
The classic joke in Boston is the old lady on Beacon Hill who was asked why she never traveled anywhere: “Why should I? I’m already there.”
Y’know, I thought of Panglossian too, and Pollyannish (sp?), but I don’t think it’s quite what the OP has in mind. Both of those are synonymous with “relentlessly cheerful,” not “so deeply but unreflectively satisfied with things as they are as to be biased against other places, cultures, methods, etc.”
“you can’t teach an old dog new tricks.”
I concur with provincialism.
Narrow minded.
Emotionally stunted/
Is all I got.
Personally the best example I used to see of this was the introduction of new computer software. People using the crappy early word processors would swear by them rather than swap to something better just because whatever they were using was “best”. After the enforced change they would soon forget their former love of MultiMate or WordStar.
I used to accuse complainants of “imaginative stagnancy” for not being able to picture anything better than what they already have. I have no idea whether I made up that phrase though.
Seems to me that Captain_Awesome got it in one. Most of the other suggestions are specifically to do with liking the place you are used to but the OP clearly wanted a word for a more general dislike of change and the unfamiliar. The word for that is “conservatism” (with a small c, and with no particular political connotations).
Human nature?
People have a natural tendency to try to like what they have and be happy with it. Some of this is a desire to have things better/be better than what other people have/are. Some of it is a repression designed to ward off buyer’s remorse. Some of it is to ward off the envy or jealousy or frustrated desire that a person might feel if he thought someone else’s car/computer/girlfriend/whatever was actually better than his. Some of it is to feel that cool wisdom and analysis was the order of the day in selecting whatever it is, and for others it’s the result of the happiness that comes from making selections based on ones’ whims or reflexive desires. Etc., etc., etc.
So basically it’s a way of keeping yourself from becoming unhappy with what you have/are stuck with on the one hand, and feeling that you are superior on some level on the other.
American?
Like I said, just plain old human nature. The same impulse that makes every 6-yo child convinced that his mother is the best cook in the world, and that the kind of spaghetti he eats is the only ‘real’ spaghetti–all others are just poor imitations.
I’ll go with EH on “complacent” as the best match. Also perhaps “babbittry.”
Robert Anton Wilson coined the terms “neophobe” and “neophile” and I think the former is also a good candidate. And I would contest that neophobia=“human nature” because I know lots of neophiles. Yeah, they get treated as freaks by the Babbitts of the world, but I don’t see any reason to privilege one over the other as the human nature. The two have been in play all through the course of civilization, and the dynamic strife between them is basically what has formed civilization.
Just because one instinct or impulse is part of human nature doesn’t mean the opposite impulse isn’t human nature as well. We’re complicated, ya know? 
When I decide that whatever I am accustomed to is best I think of it as ‘inertia’. (e.g. I use my old computer hardware and software because of inertia.)
“Inertia” is a good one. Inertia, conservatism, complacency, neophobia are all pretty similar concepts.
Yes.
The answer is: “I’m right.”
ZZZZAAAAPPPP!!!
Now, get back in line. Shut up. Be quiet. Be good.
…Or else…I get to have some fun… Do you want to have some fun???