A bug introduced in Windows 95 that they waited until 2013 to patch? I think after a certain number of years it might have moved from a bug to a feature.

For me, the problem with the new start screen is exactly what you describe. I'm fairly scatterbrained. When I'm going to open a program, file, etc., it's usually because of something else I have open, like an email with a request from a co-worker. When the start screen takes up the whole screen, I get distracted from the reason I opened it in the first place and have to go back to my email before I remember. I know that it's my problem, not Microsoft's, but at least having the choice between overlay or full screen would be nice.