time tech and the law (of physics)

while having a talk with some friends the other day, the subject of time travel came up. there were many theories and opinions. they involved all kinds of scientific principals. speed of light, Einstein's theory, the make up of the quantum foam, the effects of gravity on the time/space thingy. it seemed that all of us thought time travel was a worthwhile pursuit. then i brought up the question of what time would be like if any or all of us could surf thru time at will. could we resist trying to make changes? this seemed like a desirable opportunity to correct our mistakes. but what of the unforeseen? since it is hard enough to see all the effects of our actions now, what horrors could we unleash if we could change the past? then like a bolt of lightning a pivotal question came to me. what would happen to time if indeed we could go back in time and make changes? if we changed an outcome to benefit someone, would not their enemy go back even farther and negate it. can you imagine a bunch of us selfish humans running amok in time? whoa!!!! maybe there are some things we best not figure out. don'tcha think.... or don'tcha???