There is only one Naruto thats the hardworking who trains all time to get better.
Didn't you see Hinatas flashback when she saw Naruto training efter day even if he was in pain. The same when he learned the Rasengan,he trained the whole week nonstop despite his hands was in a great deal of pain. When he was training the last stage of Rasengan he didn't even go to sleep in the hotel.Its just like he said to Neji that Shadow replication was his worst move in the academy but he still defeated Neji with it.

You have to remember how bad Naruto was in the begining of the Manga/anime. He couldn't even do one shadow replication. So he has trained a lot to get where he is now in strengt and skill. Just because they dont show him training all the time doesn't mean that he is lazy

*MOD EDIT* - Please don't double post.