SurvivingPyrodoxManiac...
If you went back and changed the past so that you would win the lottery, would you realise or would it feel like it was always there? this one is a classic too
you would return to your time to find that everything has changed and you will at first think this is great but then pressure and lost friendships will start to weigh you down, and nobody will even find it weird that you have no idea what is going on and keep on asking questions that you would obviously know the answer to. eventually you will find this life depressing and not the life you want you will go back to the past and fix it and things will return to normal.
note: after fixing it you will go back to the future and the first person that you see, that was not themself in the other time (anyone that you talked to really), you will hug them and say such things as I'm back and ask questions about thing that you learnt about them in the other time stream, just to make sure that you are back, again they will not find this at all weird but may ask "are you ok?" or similar to witch you would reply with a corny line such as "you wouldn't believe me if i told you" or "its a long story" and they would leave it at that
((all these questions about time... maybe you should watch
back to the future, especially the second one because it goes over most of the stuff about corrupt time lines))