A well-timed laugh can let a serious conversation breathe without changing its subject.

Seriousness has a limited runtime before people start to close up. A brief moment of lightness releases the pressure without dismissing anything, and the conversation can then carry on from the same place rather than being abandoned or fought over. The skill is entirely in the timing and the target: it has to relieve rather than deflect. Done badly it looks like avoidance, which is why some people distrust humour in difficult rooms.

Watch for the point where a hard talk starts to stiffen. Let one honest, gentle laugh in, and then go straight back to the thing you were saying.