No team wishes for a Game #7 that has a lead in a series because so many weird things can happen in a Game #7.
If you want any serious data that strange things can happen in a Game #7 look no further than the 2014 Western Conference Final when the LA Kings were able to come back from a 2-0 hole against the Chicago Blackhawks.
The first weird thing was how offsides Jeff Carter was on the Kings first goal of the game. A call that prompted the offsides rule that everyone hates right now.