What is wrong with you Ubuntu?

Why Ubuntu is getting worse? When I started Ubuntu with the 8th version, everything was so smooth and fine. There was lots of options that I can change themes, styles and many other features. And now look at the 11th version. It s getting slower, problematic and so on... Moreover, it was like a MacOS that most of the features somehow restricted. I have no option to change the theme. Furthermore, I cannot find properly working commands in forums to make things customized. What now? should I pay for getting new themes? I m hopeful with 12th version of Ubuntu. But if she continues to be that bitchy, I m sorry but I have to break up with her...