If there is a hell after life on earth, then I fully expect software that does some/all of this stuff deserving of being running on computers there 24/7:

- monitoring activity without express user permission, knowledge and consent (spyware)
- reporting activity to a third party without permission and full disclosure of information being shared
- too much memory consumption
- loading at startup in systray without user permission during install and each run
- bundling other software as part of default installation
- no uninstallation program provided or uninstall program that doesn’t completely clean up trace of software (including registry entries)
- phoning home without explicit user permission. This includes backdoor installs and upgrades
- inadequate help/documentation
- using too much screen real estate, wasted space
- crippled trialware. Either go all the way or not at all
- hiding deceptive activity inside a long-winded EULA

Feel free to add to the list in the comments or via trackback from your blog.