Just like many people are riding too small or too big bicycles, handlebar size is important and might be way off on your ride if you have narrow or wide shoulders. Shoulder blade should be same size as the width of the bar but some prefer a bit wider or a bit narrower depending on what type of riding you are going to be doing. Once you put on the right size bar you will wonder why you did not do this earlier.
Then we come to the drop, classic curve or ergo, reach outwards.
Here is a good article:
Tech: How to Choose the Correct Road Bike Handlebar Size & Shape – Bike Rumor
Mountain bicycle bars also have lots of choices and are dependant on your shoulder size and what type of riding you do downhill, single track, free ride even how close the trees are on the trails you ride on. 
Mike Giant Cinelli Handlebar you have to figure out your stem length rise and handlebar size as well.
Heres Mike Giant Blog if your into art and tattoos
