#2 Daniel Bryan
Daniel Bryan is one of Shawn Michaels's students. It would be a fair assumption to say that Bryan is probably the best student Michaels has had. Unlike any other feud on this list, there is history here. Apart from the teacher-student relationship, Michaels was also one of the people that tried to keep Bryan down while he feuded with The Authority in 2013-2014.
This rivalry has a number of ways to reignite, with Michaels talking smack about Bryan, or even vice-versa. It builds and builds, and one day Michaels and Bryan meet on TV and Michaels superkicks Bryan into another dimension. That can be the starting point, and they can do whatever they want from that point onwards. This would easily be one of the best rivalries in recent memory, considering the talent involved. Make it happen WWE.