Quote Originally Posted by February
Why do you think that it is lame that Kakashi can get the MS from Obito dying?
Because:
1) Obito is (was) Kakashi's best friend
2) Kakashi's best friend died
3) If reason #1 and #2 was not enough, then here is some side explanation; Kakashi felt guilty and felt that it was his fault that Obito died, thats why in the early chapters of Naruto manga, you hear him say to Naruto's team - "I will never let my friends die again." Basically, Kakashi felt that he was responsible for Obito's death, a.k.a. killed his best friend.
Reason #1, 2, and 3 are not enough. Why? Because I don't believe it's the act of killing your best friend that gets you the mangekyou, it's the act of consciously choosing to break your strongest bonds.