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.
(..) you're gonna have to explain it to me. What is going on? Short story: You're in danger. And to keep you out of it, we have to keep you out of the obvious places, which is why you have to stay here. - But what was that thing? - Truth spell. That thing... ...was a demon. (..)1998 TvShow: Charmed Title: The Truth Is Out There... and It Hurts Season: 1 Episode 8