A small disagreement can reveal which choices were never truly shared.

Rows about something trivial are often not about the trivial thing. Arguments over a purchase, a weekend plan or a route tend to surface the moment one person discovers that a decision they thought was joint was actually made by the other and reported afterwards. The size of the trigger has no relation to the size of what it exposes.

When something minor produces an unexpected amount of heat, look for the unshared decision underneath it. Ask how the choice actually got made, without accusation. Then agree how the next one of that kind will be made, which is more useful than settling the current one.