This is my OTP and I love the simplicity of this image. While so many people keep pairing Fred with Daphne and Shag with Velma I believe that these two are the better couple.
We must look at their personalities. Scooby Doo formula is always about the fools (Scooby and Shaggy), the ditz (Daphne), the brain (Velma) and the muscle (Fred). Even when Shaggy act as a fool and a coward many times they never abandon or quit the team. They try to be brave for their friends. Daphne in the other hand seems like she prefer to join the Mystery gang because she love mystery and she want to avoid being called a typical shallow ditz. They willing to be the fish out of the water and they are comfortable that way.
So that's why I believe that they understand each other more. They are perfect for each other.