Similarities and differences between jazz and classical music

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.

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.