Throw wild weed seeds into potted plants.
This is another plan that takes some time to come to fruition. You may wish to choose a weed that contains some form of herbicide in its root system. This will damage the plants that were previously growing in the pot, and possibly disturb those who are trying to cultivate. Regardless, the morale boost that is natural plants will be undermined by your efforts.
The added benefit is the unkempt look local weeds will give to the office. Clients may question just how well the organization is doing.
* If wild seeds are not available, squash varieties grow quickly and largely.