In movies: why do villains

Tell the protagonist what their plan is?

When villains have the protagonist tied up and helpless, why do they spill their plan to said protagonist? I get that it's so that the protagonist can then escape and foil that plan but it doesnt make sense. Who would do that in real life?

Moreover, why do villains never kill the good guys when they have them tied up? Why do they repeatedly tie up the good guys, leave the room completely and refuse to monitor our good guy so that the good guy had a chance to escape?

These things always bother me in movies. Do they bother anyone else?