Phil's right, this is rather senseless.
We are here not talking about an overrated SW, we are talking about the MOST overrated SW. If GBU (or TGS or Django) is the most overrated, than it must be a bad film.
Not everybody will like them as most SW fans do, but I can't remember anyone in our forum calling GBU a bad or terrible film (which of course is possible, but I think it hasn't happen yet).
And for talking about over- or underrated SWs we had already older threads.
My favourite is still OuTW, which is also one of my 4 or 5 favourite films ever.
There were of course also lots of really bad SWs I had the displeasure to watch, but I don't think very much about them, and I don't have a clue which was the worst time waster. In fact I don't remember the titles of many of them, and I don't see any reason to compare them for deciding which is the worst. It's absolutely enough to know about a film that it was a boring film. It's not interesting to think about how boring it was, or if there are even more boring ones.
But we should name boring films so that it is easier to avoid them.