Why I hate Time Travel Movies.
The paradoxical plots involved leave you pondering all of the What Ifs of a subject that does not yet exist to know for sure what would actually be the consequences of doing so.
Most times you are left confused or frustrated trying to figure out if the premise is actually feasible without ending up in some sort of infinite time loop of cause and effect.
If I travel back in time to give myself a sandwich because I am hungry, I will no longer be hungry therefore eliminating the cause for me going back in time in the first place. The effect will be that I don't go back in time since there is no reason to....but if I don't go back in time, I will be hungry because I never gave myself the sandwich. ..arrrrgghhh!