WHY SHOULD I HAVE TO SIGN INTO MICROSOFT TO DO MY WORK?

I was able to fix my Live mail by repairing windows essentials. However I don't know why I keep getting a pop up asking me to sign into my Microsoft acct. every time I open it. I thought I disabled it by making live mail the default but its still there. WHY SHOULD I HAVE TO SIGN INTO MICROSOFT TO DO MY WORK? I am very unhappy with windows 8.1.  I feel like I'm using windows ME also known as WINDOWS MISTAKE EDITION.  Microsoft has been doing this long enough by now not to have a system with these basic problems. Obviously they didn't test it long enough before releasing it. I know people with MACS who never have these problems.  After having great success adapting to my IPhone  I should have shelled out the extra money for a MAC. Had this machine a week and already there have been multiple windows updates. For sure this is my last windows machine.