people often say "You're weird" to whoever they think that didn't fit with their er...Ideal (i hope i choose the right word)

If we analyze from that simple sentence we could conclude that the one that gives out that statement is "normal". However, what is exactly normal? People that do usually routine over and over again? or a genius that hold back when answering question to let others have a chance? It didn't quite feel right.

Hmm...let's take out an example shall we; people who hate anime/manga tend to say that otaku is bunch of weirdo. On the contrary, the otaku will think the other party is weird, like they will think "how they don't know the grand of anime" etc. In this case, there is no "normal" person.

So what is the one that define normality?
Please give me your opinion about this matter and the reason

“Normal” is anything that conforms with the individual/group, whose perspective you use, that did not get closely enough examined to make out specific unique characteristics.
People who (ab)use that word against non-conforming things have poor observation skills, imo.
I assume you meant it that way.
Another use would be to describe something as going just as usually and expected. ;o

I'm pretty much with Arglax and Redundant on this one, in terms of definition of the word. What constitutes a normal person is dependent on what group you're comparing them with, so if you're strolling around on a busy street and not doing anything that the other people aren't, then you'll be seen as normal. As soon as you start backflipping precisely every tenth second, weirdo-alarms will be ringing, and people will gaze upon you like you were a caged monkey.

In the same vein, if you're hanging out in a group where everyone else does backflips every tenth second and you DON'T do that (i.e. act like a normal person in the city), you'll also be seen as a bit of an outsider for not conforming to the local expectations. Human psychology is weird like that.

As i like to say though, normality is an illusion, and i don't necessarily consider myself a part of it. Its a nebulous enough term that it might as well not be there to begin with, and i'm almost entirely sure that if you were to pick out a completely random and seemingly normal person from the street, you'd find that this person isn't "normal" at all. Normality may be an average, yes, but the constituent parts of this average could just as well be wildly variant as they could be hovering around the median line. I have this quaint feeling that the so-called "normal" people are actually in the vast minority. :v