Lens flare is an effect created by light reflecting internally in the lens of a camera. Whether it's good or bad is up to how it's used. Some filmmakers are notorious for this (looking at you, J.J. Abrams).
Inspired by needsmorejpeg, I created an app to take user-uploaded photos and add lens flare to them. Wish your photo had more lens flare? No worries, get it automatically added for you. Just upload your photo and we'll take care of the rest. The site is needsmorelensflare.com. Happy flaring!