A suggestion box was something created by Nate and his niece on Ted's request, and delivered to the AFC Richmond locker room on Ted's first official day as manager.
The idea was that it would allow team-mates to make anonymous suggestions for improvement, largely, but not exclusively, of the physical plant of the stadium.
Most of the team members scoffed at the importance of the box, with Roy pointing out that it demonstrated Ted's misplaced priorities.
However, when he was able to actually address one of the suggestions — the low water pressure in the team's showers — Roy seemed to change his mind. While the effect on the record of the team might not have been direct or immediate, it did at least improve morale a bit by showing that Ted cared about his players' concerns.