I've attended three viewings in my life. The first was absolutely terrible. He was a green-ish color kind of like a zombie from Dawn of the Dead (Romero). He was in a horrific accident, went down a 50 some-odd foot embankment. The other two looked like they were smiling, it was really odd.
Yea one viewing I remember a guy was in a car crash. His face was crooked you could tell he had like a fractured/broken skull , but he looked like he was smiling. And another looked a yellowish color