This latrine at Ostia, though heavily re-constructed, shows that some care was taken in its decoration (the walls would have been plastered), especially compared to the "facilities" of the Middle Ages:
Of course, there were some sophisticated examples:
In the modern age, the lavatory in the Sao Joao da Madeira shopping center in Portugal surpasses all.
The Cafe Batavia has the coolest sinks.
Here's a more complete history.