RPM takes most of the work out of removing software from your system, and that's great. As with everything else in life, however, there's a downside. RPM also makes it easy to erase packages that are critical to your system's continued operation. Here are some examples of packages not to erase:
In many cases, RPM's dependency processing will prevent inadvertent erasures from causing massive problems. However, if you're not sure, use rpm -q to get more information about the package you'd like to erase.