From Digg … link.

Here is what the bars really mean and how you should react:

No bars: Wave phone around in the air like you are testing for the presence of lethal radioactivity. Make sure you have a serious/troubled look on your face so that everyone around you knows how important it is that you receive a signal. For optimal douchebaggedness, stand on something slightly higher then ground level like a bench.
One bar: If the call goes through, talk very loudly to the person on the other end, repeatedly warning them that the call might be dropped at any time. Repeat everything 3 to 5 even if they heard you the first time.
Two bars: Complain to everyone around you about your phone company and how they do not provide adequate service in all areas that you happen to go to the extent that your blossoming social life requires.
Three to five bars: Brag to everyone with less bars about how great your phone and service are. Make sure that you take credit for it, like it is somehow because of your awesome qualities as a human being that your phone happens to be receiving such a strong signal.

I find these general guidelines to be most helpful. No matter how many bars, make sure you throw in the occasional “can you hear me now?” quip, as everyone still thinks that is original and funny.