You know how some shows are 23 minutes long and some are 42? The reason for those odd times is because the shows had half an hour or an hour timeslots and the rest of it would be ads, so in an hour show you would get nearly 20 minutes of ads

What’s worse is with long running shows like mythbusters you can see the shows runtime slowly being chipped away in favor of more ads, the 2003 season’s episodes had runtimes of 50 minutes, by 2016 it was down to 42