Did Jesus have a sense of humor? Why do we view the Savior as so serious all the time?

What makes it so hard for us to view Jesus as human? Why is it so hard for us to see that He was just like us, only He did not sin? 

"For we do not have a high priest who is unable to sympathize with our weaknesses, but one who has been tempted in every way as we are, yet without sin." - Hebrews 4:15