She tried to 'smooth things out' [=end an argument or disagreement] with her daughter-in-law, but the damage was done.
They 'smoothed the way' for a quick end to the dispute. [=they made it easier to achieve a quick end to the dispute]
Her time at college wasn't all 'smooth sailing'. [=she had some problems/difficulties during her time at college]
(..) to kill two birds with one stone. Destroy a piece of corporate art... Operation Latte Thunder. Go! ..and trash a franchise coffee bar. We had it all worked out, sir. - It went smooth until... - Police! Freeze! - What? - They shot Bob. - They shot him in the head. - Fucking pigs! (..)1999 Fight Club