This bug is really important!

So this bug is really important (By the way, i am not really to sure if it can work on any versions but the one I done it in was 1.8.). Every time i go into my world or create one or go into multiplayer, I can barely move on the world, If you can't fix this, then it is impossible to play minecraft, this has been a problem for a few days now so I would really play your game a lot often. I think that the main problem is just the lag of the game it self, I have tried login out and then login in again and I even tried uninstalling it and then install it again but still didn't work. Please fix this ASAP! (Sorry, no picture to come with it because it was that laggy