Even the most aligned team disagrees. There are many reasons for that, and here are a few:
Motivation misalignment – when we use strategies to meet different needs and goals, we will likely disagree.
Emotional misalignment – when feeling disconnected, disagreeing is a natural outcome.
Assumption misalignment - assume the other party's intention without clarifying, which can lead to speculation that drives us further away.
There are no specifications on what has been agreed upon. It's challenging to know what we have agreed on if we have never experienced them.
When we know why we disagree, we are more likely to address it and make a decision.