Yep. I have rendered my Mac unbootable due to deleting files I shouldn't have. But that was a long time ago. I've learned a lot since then. And I always have my hard drive cloned with Super Duper so I can restore the system.
Hard drives are so much bigger now, so the need to delete garbage files is less. I use Monolingual because it deletes some but not all foreign language files. I use AppCleaner to uninstall programs because I have to use something, and it's free. I've never seen a program on Windows or Mac that deletes all the files related to a program that should be deleted. Additional manual removal is always required. At least on the Mac, the process is more obvious. I bought Tidy Up, which is mainly for deleting duplicates, but in that program I am much more reluctant to delete files, and many of the files it finds cannot be deleted. Even some empty folders are required by the system and cannot be deleted.
With every OS, control has been taken away from the user. I've heard some of the reasons, but generally I'm against this trend.
