Obito was such a sweet kid, with huge dreams can anda believe all the things he did?

Yes I believe that and I think I'd do the same if I was in his place! When he was dying he asked Kakashi to protect Rin and then he watches him killing her.. Madara was brainwashing him everyday so he became and exellent bad guy and assasin.

I cant beleive it, he was so cute back then! I though he was dead and when I saw in the Manga that Obito is alive.. i berkata just omg xD

At first no but then when anda think about yea.
Just when he and Kakashi was getting along he got crushed then later on saw Kakashi kill rin the girl he loved. (for whatever reason Kakashi did it for). Also for trying to kill Naruto for the nine tails still kinda hard but he knew what he was doing and won't stop till he was done his plan. I hate it that he killed konan but he didn't want anyone/anything to get in his way (but still sad!)
Also he's pretty much doing it for love
and Itachi berkata hatred makes anda stronger witch was true it was because he hated what Kakashi did that he is where he is and like nagato said(i think not sure) war makes u grow up. When obito was growing up there were still lots of wars and it was most likely because of the war Kakashi killed rin