Reason No. 1: It’s masculine
The world’s most manly men (Tom Ford and David Beckham come to mind) are pretty much always in some sort of blazer, which is basically like an express ticket to Testosterone-ville. After all, the only reason people care about clothes in the first place is to attract other people so that they can take them off. 

Reason No. 2: It hides doughnuts and pizza
A formfitting blazer can create a completely new silhouette for your body - even if you’ve been skipping the gym. Whether it's love handles, a spare tire or flabby forearms, the clean lines of a blazer will instantly lean you out. 

Reason No. 3: It plays well with others
The blazer is one of the few items of clothing in a man’s wardrobe that can work with anything from black tie to a T-shirt. In short, the possibilities are endless. Of course, just any old blazer isn’t going to get you laid, drop 10 pounds or integrate seamlessly with a cummerbund.