"Acid" does not sound very appetizing, nor does "sour". But mastering acidity is a big step towards mastering the art of flavoring food.
Without it neither salt nor sweet develop their full potential. Adding a little acidity brings out the freshness and makes your taste buds tingle. Every serious chef knows a thing or two about acidity:

 
            
        
        
            

 
                    
                     
                    
                    