Answer:
Word Choice.
Step-by-step explanation:
Mood can be created and influenced by many things, but title, length, and ending aren't some of them. I could say the same thing with two different moods depending on my word choice. I could say "Thankfully, Grandmother passed away!" Which obviously creates a very happy mood, or I could say "Unfortunately our beloved Grandmother has passed away..." Which obviously creates a much more sincere and emotional mood.