MacBook – Shiny new Macbook Pro — can oils and sweat damage the screen

The reason it's brighter is because water has a refraction index that is closer to 'glass' (as in the specific material used in the screen--I know it's not really glass per se) than air does. This means that less light is lost in the area between the LCD and the front glass (or between the LCD and the backlight--but not very likely) and thus the screen appears brighter.

You'd probably get a better explanation on Physics in terms of specifics, but this is the answer in a nutshell.

It is just a matter of time. You do eventually get used to it (I had to). However, the glare will almost always be noticeable. Unfor tunately, this is because of the glass used on the screen. If this is really bothersome, make sure you order the non-glossy screen (another $150). The new retina display MacBook Pro and the newer MacBook Airs have a less glossy screen that the current MacBook Pros.

If it really bothers you now, you may want to look into getting a screen protector. Here is a MacWorld article comparing a couple protectors. I also found one on Amazon. I will note that I have never used on of these.