The person who lets your good mood remain yours has offered a quiet kind of generosity.

Good news attracts qualification. Someone points out the catch, mentions the harder version they went through, or moves the conversation to their own week, and the lightness you arrived with gets managed away. Letting it stand, without a correction or a comparison, takes a small act of restraint that nobody ever notices.

When someone comes to you pleased about something, be pleased with them and add nothing. Save the practical caution for another day, and let them keep the whole of the good hour they brought in.