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.
(..) The first morning I was with him, he made me eggs just like this. - Really? - I swear. That is a strange coincidence. Although there's an obvious explanation. - There is? - Yes, Evey. I am V. At last you know the truth. You're stunned, I know. (..)2005 V for Vendetta
(..) - - Dascomb. - - - What situation? Chancellor Sutler agreed, for obvious reasons, we have to keep this discreet. In the wrong light, the loss of the Voice of London... ...could be devastating to our credibility. Perhaps a stroke? (..)2005 V for Vendetta