Ramble Shramble

Ever came to one point in your day where you meet someone that has some choice over the course of the rest of your day? Sure you have. Ever developed an opinion on the person based on his choice; the choice that will affect you?
OK, this calls for an example.
Say, the cleaner is mopping the floor in school, and you know he doesn't like people stepping on his freshly chlorinated floors. So this time, the entire narrow strip of corridoor is wet and you need to pass but you have to step on it. The cleaner looks up at you and he can give you 2 responses:
1) Boy, don't step ah prease!
or
2) Go ahead, go ahead, its ok.
and you develop two different types of opinions based on his response:
1) What a lonely old man!
or
2) What a nice old man!

The thing is why can't we ever be neutral on something. Not facts or funny issues like abortion or what-have-you-stem-cell-research. I'm asking questions about why feelings can't be neutral. Why can't we have a lah-dee-dah attitude.
Why do we have to develop first impressions of people immediately?