If you know *why* something shouldn't happen, then it bothers you 100 times more. If you don't, you are more likely to accept it and enjoy the explosion or whatever. Since most of us are in fact neither physicists, or mythbusters (though /. obviously has a much higher % than the average), that makes it a lot easier to accept something that physics would not normally allow.
Case in point:
Nothing bothers me more than some hacker logging into a highly encrypted system in 5 seconds and then, having never been in the system, within 15 seconds re-writes the security codes to allow doors to open. Or some other crazy real-life effect. Why? Because I am a programmer, and I know how hard it is to not only get into a system, but to also find the thing you are looking for on that system, and then to make real-life effects occur without undesired side-effects.
But this is a necessary conceit for most tv and movies because generally spending 20 minutes on a montage of poking through someone else's system (assuming you even got in) is not entertaining, and neither is establishing a backstory for a hacker that they somehow know 0-day exploints into every version of every type of server and application ever. So I learn to let it go.
However when it comes to things that I don't fully understand the rules that are being broken, I am much more likely to give leeway, because, again, I just don't know for sure. Sometimes shit happens 1 out of 1000 times, and when it does, it makes for an entertaining movie.