Shared memories become richer when nobody insists their viewpoint is the whole event.

Any event that involved several people happened several times. Each person was standing somewhere different, worrying about something different, and hearing a different half of the conversation, so their accounts differ for reasons that have nothing to do with honesty. Treated as a competition, this produces an argument about who was really there. Treated as a collection, it produces a fuller picture than anyone had at the time.

Next time you are reminiscing and someone contradicts you, ask what they remember rather than correcting them. Add their version alongside yours instead of choosing between them. You will often end up with a detail nobody had access to.