1.)Agree 100%
MD is an ok song, but from what I recall, many reviewing BOMB thought it was an absolute stunner, a stand out, even on an album they rated extremely highly. It's certainly not that. It's just good, and that's not saying a lot when U2 has spectacular songs that are so underrated, like Love Comes Tumbling!
2.)Most Overrated: Stuck In A Moment. I like it, sometimes even a lot, but it's nowhere near as good as the band, critics, radio and general public seem to believe. Especially between 2001 and 2003.
Most Underrated: Stay(Faraway, So Close). This question has always been really hard for me. I think Trip Through Your Wires, Ultraviolet, Two Hearts Beat As One, Please and Gone are equally underrated. However, Trip, UV and 2 Hearts were all on well known albums with very strong sales released in an era when you actually listened to and digested the entire album. So they are actually pretty well known. I talk to people about U2 and bring up these songs and a good amount of them will remember and like them. Please and Gone are certainly rated correctly here on this board and both have some exposure for their widely known subject matter- The Troubles/Peace process and Michael Hutchence(the meaning Gone took on after 1997). I think Please was written up very favorably by Pop reviewers as well. Plus, both songs got played live for a full tour.
By contrast, Stay was on a pretty under the radar screen U2 album that was regarded in many critics' circles as merely a not-as-good companion piece to Achtung Baby. To the extent Zooropa was noticed by the public at large, Stay took a backseat to Zooropa, Numb and The First Time. It was only played live in full form for maybe half of a tour leg and then only saw rare acoustic performances on 360. The closest it ever came to live regular was occupying a rotational slot for a whole leg of Elevation, which it had to share with 2 or 3 other songs. Some may say "but Gone wasn't even a single, Stay was and it even "stayed" on the charts in the UK and Australia for a bit!" However, Gone made the best of 1990-2000, more a casual fan/general public album while Stay was left off!
In addition, Bono has cited it as one of his personal favorites and possibly the band's most underrated song!
And finally, it's just absolutely gorgeous. Mind blowing, intimate yet universal. The lyrics, the melody, the way the Edge soars, the perfectly placed cymbal crashes, Adam's bass line, everything is just perfect. Bono turns in one of his most powerful and emotional vocal performances. He makes you feel like you are truly in 7-11, truly talking to and being highly attracted to and interested in someone who doesn't return your interest and doesn't want your help. It's just incredible. In fact, in and of itself, it could single handedly make the case for Bono writing a movie or a screen play. It's just that evocative.
So there you have it, I got a little (or a lot) long winded there, but with so many underrated songs, I felt I had to justify my pick!!
For the record, Trip Through Your Wires was my knee jerk reaction and emotional favorite before I really thought it through. And that is due only to how CRIMINALLY UNDERRATED IT IS BY THE MAJORITY OF THE PEOPLE HERE AT INTERFERENCE!