I'm a web developer and wanted to install Opera so that I can test my work on this browser too.
I was honestly shocked by the installation process. The first screen asks you to accept conditions, and is built in a way that it's easy to overlook the "Options" dialog, even though it does some pretty consequential stuff: it has the option to change your system's default browser, as well as the setting to start Opera on system startup AND the setting to allow sending usage information. All of these are checked by default.
This is obviously intentionally designed to make as many people as possible leave these options on without even knowing they did it. There is no other reason to not do the user friendly thing, which is just showing all these options directly on the form where you're agreeing to them. There is plenty of space for that.
<< There would be 2 screenshots of the installer here, but apparently image uploads cause a 403 error, but it's easy to observe. Will try to add these images later. >>
Then, the next step is similarly, though here at least it's a bit more obvious. You're agreeing to every possible privacy concerning option by default and need to navigate to another screen in order to see them. This includes, among other things, targeted ads based on your browsing behavior.