Don't get me wrong, I love time travel stories when done right. Star Trek's "City on the Edge of Forever" or the Terminator movies still entertain me after multiple viewings. But they are not always done right. Time travel stories have risky pitfalls at every turn -- one minor paradox or lapse in continuity ruins the entire story.
The Internet is buzzing with the viral video of a short clip from an old Charlie Chaplin movie that shows a lady who seems to be talking into a cellphone -- before cellphones existed. Imaginative viewers are hollering "Evidence of time travel!" My speculative fiction loving heart enjoys "what if" fantasies, but my skeptical mind cannot believe that time travel could ever work, even in a fictional setting. It's a lot easier to think the lady in that old silent film is listening to a hearing aid than conversing through some space-age technology from the future.
I know there are theoretical physicists out there who could offer evidence that time travel is plausible within our current understanding of the laws of physics. But it still requires a leap of faith to conclude that human beings can time hop.
I lean on the side of those who believe that our universe has some built in roadblocks that make travelling through time impossible. These safety measures protect the space-time continuum from any damage that traveling to the past or future might create.
So even though Back to the Future is one of the best and Bill and Ted's Excellent Adventure is one of my guilty pleasures, every time I come across a time travel tale, my sense of disbelief is difficult to overcome.