A departing colleague can be missed for habits nobody thought to praise formally.

What holds a workplace together is rarely what gets appraised. Somebody made the coffee, knew which supplier to ring, noticed when a new person was struggling, and none of that appeared in a job description or a review. Their absence is felt immediately and is hard to name, which is why the first weeks after someone leaves feel oddly effortful.

You can say this while it still reaches the person. Tell a colleague which of their habits makes your week easier, using specifics rather than general praise. Do it before a leaving card makes you find the words in a hurry.