adj: sullen is the description of an unenergetic, silently ill-minded, quiet person.
usually this feeling occurs when a person is mad but cannot express his/her feelings properly and fails to communicate with his/her audience, creating an awkward and general feeling of uneasiness
Context: Dillian is mad because Josephina and Mildred pissed him off.
Jospehina: "Dillian what's wrong?"
Dillian: "....... (angry face showing his silently ill-minded mind)"
Mildred: "uhhh are you ok?"
Dillian: ".......(making situation gradually more awkward)"
Geutrude (girl's name): "what's wrong with Dillian?"
Josephina: "uhh i don't know he won't say...."
Dillian: (looks off into the distance, looking very angry, but still failing to describe how he feels)
(As Dillian looks into the distance, Josephina and Mildred leave, awkwardly leaving Geurtrude in silence with Dillian)
In conclusion, Dillian's sullen attitude made the entire situation BAD