Her reasons for leaving were 'obvious'. = It's 'obvious' why she left.
You are stating 'the obvious'. Tell me something I don't already know.
Her doctor immediately noticed the 'obvious' signs of the disease.
(..) May I remind you this is blitz chess, A single miscalculation will cost you the game. If tackle the wrong man to the ground, I could start a war. Maybe it's less obvious... A nervous tic. A flutter of anxiety. I'd expect everyone has a reason to be nervous tonight. I don't know. (..)2011 Sherlock Holmes: A Game of Shadows