Musically, the song is a glossy take on a basic grunge music format, with delicate, sparsely-instrumented verses alternating with loud, aggressive chorus sections.
Lyrically, the song consists of a series of vignettes describing situations, each ending in the repeated question "Isn't it ironic?" For example:
The song's usage of the word ironic attracted attention from people concerned with the precise use of the English language.
Supporters argued that the song title used the word ironic correctly in the casual sense. They argued that it was self-referential, and that the irony consisted of the song's use of the word ironic to create an expectation that the song would be about irony, followed by the incongruous presentation of situations that were not ironic.
Some of those familiar with the song and the usage debate invoke Morissette's name in reference either to the sloppy usage, or to the subtly self-referential usage of the word ironic. It remains to be seen whether phrases such as "Morissettian irony" will enter the common lexicon. It is possible that the song marks a trend toward increasing acceptance of what as of 2003 is still considered sloppy usage of the word irony.