The magic word I alluded to in the subject line is the word "because".
If you use the word "because" in the right manner, you can get people to do things with less resistance. This includes children, bosses, spouses, friends, strangers, store clerks, etc.
The way to use the word is to use the following protocol:
1) state your command/request
2) say "because"
3) state any reason.
At this point you might be thinking that I'm crazy, and that this is just too obvious. Believe me when I tell you that it works because I've ready the study that proves it.
The reason that you provide in step 3 does not have to make sense. The word "because" is a funny word that has been proven to affect people. When you hear the word "because", you simply assume that whatever follows it is a valid reason. It is an automatic function of the human brain. Just like you'd automatically pull your hand away from a hot stove top, you are literally programmed to treat "because" as a word that comes before a VALID reason. Therefore you tend to almost outright ignore the reason.
Suppose you have a 8 year old son, Tommy. He hasn't cleaned his room. You can say to him, "Tommy, clean your room because we're going out for dinner later".
What the heck does going out for dinner have to do with cleaning his room? Pretty much nothing. But this tactic works most of the time.
Try it out for yourself. It's fun.