A leaving present that isn't a card
The whole office signs a card that gets read once. A shirt about the specific thing they were known for is the version that survives the next job, and the one after that.

A leaving card gets passed around for two days, collects eleven variations of good luck!, and is read once in the car park.
The reason it's the default isn't that it's good. It's that it was the only thing that could be organised in a week by somebody with a day job.
What changed?
The lead time and the minimum.
Making a garment for one person used to require a decision three weeks early and a quantity nobody needed. Which meant leaving gifts defaulted to whatever could be bought on the way in: a card, a mug, a plant.
One shirt, ordered on the Tuesday, is now a normal thing to do — the smallest possible order is one, and that's what makes this category exist at all.
What goes on it?
The thing they were known for, stated flatly.
Every workplace has a fact about each person: the one who fixed the printer, the one whose reply was always ok, the one who never used the calendar, the one who had opinions about the dishwasher. That's the material.
The register that works is deadpan and official-looking — varsity block letters, a badge, a department stamp — applied to something completely trivial. The comedy is the gap between the seriousness of the format and the pettiness of the subject.
Why does the flat, official register work?
Because the joke is the format, not the words.
FORMER COLLEAGUE in collegiate lettering with a number under it is funny because it's the typography of a championship applied to somebody leaving a job in insurance. Written in a soft script it would be a sentiment. Written as a sports honour it's a joke everybody in the room gets.
Same move as a hazard label as a costume: borrow a format that carries authority, point it at something that doesn't deserve it.
What's the number for?
Years served, and it should be exact.
09 reads as a jersey number and is actually nine years of their life. That double reading is the
whole design — it looks like sport and means tenure, and the person receiving it knows precisely
which nine years.
For a short stint the joke inverts and gets better: 01 on somebody who lasted eleven months is
funnier than a long number.
Is there a line I shouldn't cross?
Two, and they're both about who the joke is aimed at.
Don't print a joke about why they're leaving. Redundancy, a bad manager, a resignation nobody was supposed to know about — a garment makes that permanent and public, and the person may need to wear it around people who don't know the story.
Don't make them the object. A joke about their habits works when they'd tell it themselves. A joke about their weaknesses is a shirt they're the target of, which is a different and worse gift.
Who signs it?
Nobody. That's the improvement over a card.
The temptation is to have the team sign the shirt in marker, which turns a garment into a card with sleeves and makes it unwearable. If the group wants their names on it, they go small on the back or the sleeve, printed rather than written.
Left unsigned, it stays a shirt — which is the point.
Does it work for someone retiring?
Different object, and worth separating.
A retirement is a whole career and it deserves the technical register: the machine they knew, drawn properly. A leaving-for-another-job present is a joke about an ordinary Tuesday.
Getting those two the wrong way round is the main way this goes flat.
How do I get one made?
Describe the joke at JustOG — what they were known for, and how many years. Pick a direction, drag the crop frame, see it composited on the real garment, and it's made to order and shipped.
Designs other people have published are in the shop.
The card gets read in the car park. The shirt turns up at the next job.