The most important function in the first few seconds of a television commercial is to:

The most important function in the first few seconds or a television commercial is to grab the viewers attention. 

Why? Because if the person thinks the commercial is boring they're gonna go get a snack or skip channels, basically, commercials are so common no one wants to watch a boring one.

Think about the Super Bowl commercials. They’re so well made that people will go back to watch them later. That’s because they are very interesting. People like to watch interesting things.

Hope this answers your question, and May the Force Be With You!

-Jabba