Similarities and differences between jazz and classical music

Similarities: They've both been rather popular in about the same time period, and both are played by similar differences.

Differences: Jazz is still regarded as good music and is associated with happiness and upbeat things, classical is usually associated with boringness, boredom, sadness, etc.

Classical music is almost always written with fixed compositions, while Jazz favors improvisation and individual interpretation. Classical is composer driven; jazz is performer driven. In Jazz, rhythm plays a major role but in Classical it is a subtle element that is definitely less prominent.