I switched from XP to 7 quite late in the day (skipping Vista), then changed jobs and had to switch to 8 fairly soon after. Now you mention it yes, the little preview windows were an annoyance that came in with 7.

I thought 8 came with all that see-through nonsense too - just that 7 had taught me how to turn it all off! My windows are all satisfactorily opaque, now, and nothing animates when it could just snap. It's very restful :)