There has long been a theory which states that if no cat is present, mice will engage in a variety of leisure activities. Could this really be true? Science and Googles have observed mouse/feline interactions and produced this chart.
As you can see, from 1800 to the present day, cat absence levels (represented here by the blue line) have fluctuated wildly, due to the unpredictable nature of felines and the availability of warmer places with better food, regardless of the fact that you do everything you can to please the ungrateful little beasts.
Mouse recreation levels on the other hand (shown here in red) remain resolutely at zero regardless of the presence or otherwise of Tiddles. Mice, it seems, simply refuse to enjoy themselves under any circumstances.
In conclusion then: it appears that while the cat's away mocking your kindness, the mice will stubbornly continue to sulk and fixate on cheese. And not play.