If you think choosing precisely the right words doesn't matter much, you're wrong. A single word can have amazing power to change human behavior, usually without our being aware of it. Which means those who know how to use powerful words convincingly have an advantage over everyone else. 

Consider the following amazing experiment performed by social psychologist Ellen Langer, and recounted by Buffer's Kevan Lee as an intro to his Big List of 189 Words That Convert, which is very much worth a read.

Langer walked into a series of copy shops (this was before we all had printer/copiers on our desks) and asked the people waiting in line to make copies if she could cut ahead of them using three different specific phrases:

"Excuse me, I have five pages. May I use the Xerox machine?" When she asked it this way, 60 percent of the people in line agreed.

"Excuse me, I have five pages. May I use the Xerox machine because I'm in a rush?" This time, 94 percent of the people she asked agreed. Makes sense--we've all been in a hurry one time or another and the people around us are often kind enough to accommodate us at those moments, so we tend to give back by doing the same for others.

But here's where it gets interesting. In some cases she said, "Excuse me, I have five pages. May I use the Xerox machine because I have to make some copies?" That's completely meaningless--presumably every customer in a copy shop has to make copies. Nevertheless, 93 percent of those she asked agreed to let her go first. That's the power of a single word--the word "because." It's one of the most persuasive words you can use.

Here are 37 more.

The most powerful word you can use:

1. You

Like most humans, your readers and listeners are primarily focused on themselves. Yes, it's a good idea to speak or write about yourself and your experiences as a way to create a bond with your audience. But before you do that, you need to engage their attention, and the best way is to let them know right from the beginning how what you have to say will benefit them. That makes "you" the single most convincing word you can use when writing or speaking.

Words that convey urgency:

All of us are too busy, and constantly facing competing demands on our attention and time. Given this reality, why should anyone stop and read or listen to what you have to say? Because whatever it is is urgent, and requires their immediate action. These words to convey that notion.

2. Now

3. Need

4. Must

5. Must not

6. Don't miss

7. Latest

8. Hurry

9. Only (as in "only three days left" or "only five available")

10. Today

11. Tomorrow

Words that create connection:

We spend more time connecting with others on social media than we ever have before and yet many of us are also lonely. The trend toward working at home--a wonderful thing in most ways--makes this problem even worse. Your readers and listeners are looking for a sense of connection and community; here are some words that will give it to them.

12. Join

13. Help

14. Discover

15. Create

16. Come along

17. A good fit (as in "our product may be a good fit for your needs")

Words that help people trust you:

"Because" fits into this category, along with many other words and phrases that imply cause and effect. The reason, according to Darlene Price, author of Well Said!, is that cause-and-effect words and phrases make you seem objective and rational. This list of words includes some other good cause-and-effect words, as well as other words that imply you are both objective and trustworthy.

18. As a result

19. Consequently

20. Caused by

21. For this reason

22. Proven

23. Research

24. Results

25. Secure

26. Tested

Words that promise a reward for little effort:

In our busy lives we are constantly, often unconsciously, calculating how we can best spend our time to get the most useful result. That's why it's a powerful tactic to use words that suggest that a small amount of effort--such as the few minutes it will take someone to read your message or listen to what you have to say--will bring immediate benefits. One warning though: Do not use these words and then fail to deliver the goods, or you risk alienating your audience. And that's tough to recover from. 

27. Quick

28. Easy

29. Instantly

30. Immediately

Words that promise a surprise:

In modern times we've all become a little jaded, and we're all on the lookout for anything truly unexpected, especially so we can share it with our friends and on social media. These words tell readers or listeners that what's coming next will surprise them in some way. Here again, do not use these words unless whatever follows truly lives up to that promise:

31. Surprising

32. Remarkable

33. Amazing

34. Astonishing

35. Startling

36. You won't believe

37. Unbelievable

This should give you a good start, but there are a lot of other powerfully convincing words and phrases out there. Share your own favorites in the comments. (And see how many of these you can spot in Inc.com headlines.)