Jagr has done practically everything imaginable in hockey. Olympic Gold, World Championship Gold, 2X Stanley Cup Winner, 5X Art Ross winner, 3X Lester Pearson winner, 1X Hart Trophy winner, 10th all time on the NHL scoring list. Oh, and at the age of 36 he decided to head to Russia to help the upstart KHL get going where he lead his club team Avangard Omsk in scoring & finished in the top 10 in league points.
Jaromir really has nothing to prove. But he probably doesnt see it that way. The NHL world (namely the fans & media) has essentially cast him aside as washed up. His last NHL season was very unspectacular by Jagr (71 points in 82 GP) standards & many thought he was losing a step. So he headed to Russia & played very well there, but many in North America still dont take the KHL all too seriously. So he is for the mostpart seen as "washed up". But thats hardly the case.
JJ will be in Vancouver showing the world he still has "it" & that the NHL is missing "it". His KHL contract is up at the end of this season & its widely speculated he will be using the Olympics as his audition for an NHL job next season. So yes, Jagr has lots to prove.
The Czech Republic is hardly a medal "favorite" by anyones rankings this Olympics, but with Jaromir Jagr on the team those odds get better, and with him wanting to go out & prove he is still a force in the game he was dominant at for more than a decade, a medal suddenly seems very possible for the Czechs.