I hope you realize that there are many situations when doing something in OS X and/or Windows is more complex than it is in Linux. Unfortunately, the different strengths and weaknesses of these operating systems makes it exceedingly easy to cherry pick examples and counter examples.

Take installing hardware. If your Linux distribution supports a piece of hardware, you can usually plug it in and expect it to work. That only sometimes happens under Windows. While OS X is similar to Linux in this respect, Linux supports more devices in most categories. Of course you can always choose the counter example of unsupported hardware. Short of outdated hardware, Windows will likely support it. The installation process is usually more involved, but that is nothing compared to the contortions that some Linux users go through in order to attempt to get something working.

Or take installing software. If you're sticking to open source software, the process is usually: click on icon to load the "store", click on search field, type in search terms, click on a result to see a description and screenshots, (repeat until you find what you want), click on the install button, (wait for download and installation), click on program icon to use the program. You also have a categories option if you would rather browse for software. In the case of Ubuntu, you even have this option for some commercial software. Apple and Microsoft have store that enable a similar path to be taken for a small subset of software. In reality you usually have to obtain software through other means. Whatever means you choose, the discovery process is more complex. When you get to the installation phase there are varying degrees of interaction. That interaction ranges from double clicking on the downloaded file and dragging the program icon into the Application folder in OS X, to installers of varying complexity in OS X and Windows. In the case of installers, Windows installers are almost universally much more complex than those in OS X. Of course some Linux software is not distributed through the package managers (ahem, calibre), in those cases you're talking about anything from a Windows level of complexity, or worse. Yet the vast majority of software installations under Linux does not involve a separate installation step at all.

The list can go on, depending upon which scope of features you examine and which subset of exceptions you consider meaningful. On top the of generalities, you also have to consider that some users will run into far more problems than others (regardless of platform) simply on the merit of what they use their machine for.

Except that the printer would have worked without issues if they bought one that is known to work with Linux. Now I know that you can pick up any old printer and expect it to work under Windows because every vendor supports Windows. They would be foolish not to. That's one of the advantages of Windows. But let's look at things from a different angle. People malign OS X for it's printer support much less frequently. It isn't because OS X provides better printer support. It is because Mac users typically verify that the printer supports OS X prior to purchase. People seem to have double standards.