Have you ever taken a photo and your subject came out on the dark side, underexposed,? Your meter mode that you choose even read that you were all set for a perfectly esposed shot, what's up with that?
The reason could be that you weren't using the proper metering mode.
Here is a great article on the differences of your cameras 3 meter modes
Introduction to Metering Modes - DPS
Metering Modes Explained - DPS
I have to admit that I am a CW (center weighted) Metering Mode Person. I figure that most of the time what I am going to be shooting will be in the CENTER (or close by) of the viewfinder. I have on occasion used Matrix and I very rarely if ever use spot.
There really isn't a right or wrong way to meter, it's really a personal thing and what the situations calls for.
Play around with your cameras metering system. Become familiar with how it works and what you like best.