resting derp face

A relaxed facial expression which perpetually holds an expression which can often be described as cute, awkward, and somewhat silly.

The word "derpy" is often used to describe such people.

Eric and Joe: Hi, Matt! :D

*Matt smiles awkwardly and gently waves as he passes them*

Eric: Aww, Matt's always so derpy all the time! I love that guy.

Joe: It's kind of his thing. He has resting derp face.