The reflex is to mark the achievement. A pen, a plaque, a bottle with the old company's logo on the box. All of it points backwards, at the thing they have just finished, when the person in front of you is quietly terrified about Monday.
What actually helps is smaller and stranger than a plaque. The twenty minutes at the start of the day that stop belonging to somebody else. The thing on the desk that saves them having to introduce themselves. Lunch that is worth packing. The jacket they already own, made to fit. The hour with somebody who has already done it.