This was the second anime i ever watched online, the first one was Panty and Stocking with Garterbelt but i hated that one, man, i remember i was hospitalized so i , for once, wanted to watch something rather than play something, so while looking at a Smash Bros parody i found this one awesome crossover video of Puella Magi Madoka Magica and Captain Falcon, said video convinced me and i started watching, holy shit did the feels and overall themes hit me hard, i fucking loved everything about it, i went ahead an even showed it to several friends and so far all of them has loved it, i haven't watched Rebellion because i don't need to since my GF spoiled the third movie to me.
Also, it was thanks to Puella Magi Madoka Magica that i took what probably was the best decition i've ever done, watch One Piece, that manga/anime changed my life forever, and now both Madoka Magica and One Piece have special places in my heart forever.