In simple terms, OpenGl is nothing more than a cross platform solution that does what ActiveX does for Windows applications, only it works on all major OS's.
You don't have to get it.. you just have to have a video card that supports it.
Most cards now-a-days do, but only after you update your card's drivers to the latest offered by the card manufacturer. If you are having graphic issues, then the first step you should try is to go the video card manufacturer's website, download, and install the latest drivers they offer for your installed card.