Their works of art, mostly paintings, are usually middle-of-the-road products, with cliché themes and compositions. Someone made a study of themes in Dutch amateur art: portraits (27%), endogenous animals, like tigers, elephants (15%), landscapes (15%), dogs (12%), children (9%), birds (8%), abstract (5%), nudes (2%), and finally, cats (1%). I am surprised that cats are at the rear end, given cat popularity in Holland.
Amateur art has clearly a strong preference for realism, the painted figures should be recognizable. This type of art will not shock, nudes will not be offensive. It's interesting that abstract art is usually too difficult for them.
Amateurs just paint for fun. Sure, they hope to reach a nice end result, but in the end the process itself is the most important.