It's not really arbitrary at all - if you try to do something that will put abnormal stress on reality, the tension headache starts with you. The ordinary violations of causality like calling yourself to ask if that new movie was any good and deciding not to waste the money when you tell yourself it was crap, that's minor, barely noticeable even, it's something that could be waved away with a case of deja vu. Specifically thinking about trying to break the universe for kicks, like by calling and getting an answer and them planning to specifically not pick up the phone when it rings with your past self, is bout as obnoxious as a shift on the cash register at the toy store during christmas shopping season. Sure, you can push through it, could every day for weeks if you had to, but why would inflict that on yourself unneccesarily? Bigger exploit, bigger headache. Actually pulling off something that would cause a physical paradox might well become a health hazard - finding a way to be in two places at once would probably mean you're both unconscous, and if you actually shake your own hand your head a'splode!
- CD, play nice with the time machine and it will play nice with you, try to screw around and you'd best be prepared to be the first one getting lubed up
--
"Anko, what you do in your free time is your own choice. Use it wisely. And if you do not use it wisely, make sure you thoroughly enjoy whatever unwise thing you are doing." - HymnOfRagnorok as Orochimaru at SpaceBattles
woot Med. Eng., verb, 1st & 3rd pers. prsnt. sg. know, knows
- CD, play nice with the time machine and it will play nice with you, try to screw around and you'd best be prepared to be the first one getting lubed up
--
"Anko, what you do in your free time is your own choice. Use it wisely. And if you do not use it wisely, make sure you thoroughly enjoy whatever unwise thing you are doing." - HymnOfRagnorok as Orochimaru at SpaceBattles
woot Med. Eng., verb, 1st & 3rd pers. prsnt. sg. know, knows