I hate to argue, but…
Conflict creates tension, propels a story forward, and keeps the reader engaged. And there’s nothing like a good argument (a literal conflict) to set characters at odds, amp up emotion, and get to the core of who a character really is under pressure.
Choose two characters from your story. Put them in a room (or car or bank vault or Hobbit hole) together and start an argument.
Stuck for ideas? Here are some universal sources of conflict:
The in-laws
What to watch on TV
An impulsive purchase
A secret unexpectedly revealed
Politics
A lie
The kids
Conflicting memories of a shared past