Why is midnight is the end of opportunity? When I'm watching TV it's always by midnight, if unable to be stopped by midnight it'll never be stopped. Like if I built a magical device to rule the world but it'll only work at midnight or I got magical powers and if I wait until midnight then no one can stop me. Why is midnight the start of the day? Why not 6 am or something?

Midnight is the time between days. It is the exact end AND exact beginning of the day. It is also a time when the veil between the worlds is thinner than any other time during the day. It's a gateway between the old and the new.

That being said, don't believe everything you see on TV. Even though midnight DOES hold power, it is not the all-important hour TV makes it out to be. Real magic relies on the spirit of things, more so than the literal definition. Doing a spell AROUND midnight is usually just as good as doing I exactly AT midnight.

Besides, who's to say your watch isn't off by a minute or two. Have you ever wondered what would happen if the people on TV had different times on their watches?

A lot of it, is for dramatic effect. There's something final about hearing the first gong of 12 as a signal that things are over, for good or bad. TV, and movies, almost always have a large clock with a loud, deep tone to strike midnight.

I don't believe that TV stuff but it made for a better example. TV tends to copy old cultures and beliefs.

well, then, ignore my last paragraph ^_^

the rest still holds true.