Which is better coding style?

Is better to code
1. In a way can be readable easily on first sight but maybe inefficient
or
2. That is very efficient and short but more complicated to read and understand

My instructor (a very scary prof) always tells us to go to option #1. Yes you can still do option #2 if you provider enough comments to explain.

But if you do option #1, you will not need to comment alot about your code because your code will speak for itself because of its easy readability.

What do you think?

>>17
This article is not that bad at all. In fact, I agree with most of it, only adding that class name shortening, whitespace and comments removal, and color shortening should be performed:
- Not in the original files
- In the production files
- By a script
This is what some sites like Google do to be that fast. Have a look at Google's HTML and JavaScript.