If Trump acts like a true businessman he may succeed in operating a (probably needed) reset of the relationships with America, Europe and Russia.
Conversely, he may act like a fanatic nationalist and worsen the frictions. Who knows.
This whole idea of a reset extends to personal relationships on a mundane level as well. If two people are receptive they can reset a relationship but often old patterns creep in again. It is difficult to forget old patterns unless you get some kind of apology although we may hope to get one they may too which then becomes perception. Everyone has their own narrative their own story.