I hate the People/Contacts list in Android so much that I'm seriously thinking about leaving the Android system.

(I'm referring to Android "fishing" any and all persons you have ever e-mailed, phoned, skyped, etc ... and building a contact list based on this. I also hate - to a slightly lesser degree - that Android "pushes" new versions on you, with "new and improved features" and don't let you decide if you want to keep the old or the new way).

I'm NOT considering a move to Apple.

So, a question to Windows Phone users: How customizable is it? As much as a Windows (computer) environment? Any drawbacks? Please share your experience.

And to a more general audience: are there any (fully customizable) option(s) to Android / iOS / Windows Phone?

(I have some technical knowledge with (Windows) computers, not so much with phones, smart or not; so not shy on learning other OSes, if necessary)