I love hearing managers complain about unions.

“You can’t get those guys to take responsibility,” they complain. “They’re just not motivated. Don’t blame me — they belong to a union!”

Union members who won’t take responsibility? Didn’t I just hear the manager refuse to take responsibility for motivating employees? It would be one thing if motivating union members were impossible, but it isn’t. I’ve seen it done, and in small ways I’ve done it myself once or twice.

Employee motivation is one of your most critical responsibilities as a manager. Last week we talked about the five great motivators, learned from my personal marketing guru (aka Dad): fear, greed, guilt, need for approval, and exclusivity. We explored fear and its limitations. A last thought: Don’t confuse fear and intimidation. There’s never an excuse for bullying an employee. Bullying is simple self-indulgence.

How about greed? Managers misunderstand and abuse greed more than any other motivational technique. Managers who don’t understand how to motivate union members share a mentality with those who rely excessively on the compensation system as a motivator — they think employees do it for the money.

Outside of sales, greed has big problems as a general-purpose motivational tool. You can apply it in four ways: salary, spot bonuses, annual incentives, and stock ownership. Salary is the worst. Let’s take an employee who earns $50,000 annually and try to use his salary increase as a performance incentive. Let’s imagine your company has established 4 percent as its standard raise for average employees. You squeak out a 7 percent raise for a great performer — way above the average. Wow! After taxes, your great performer will take home less than $20 a week more than an average one. If you think that will motivate someone to excel next year, you’re living in a fantasy world.

How about spot bonuses? They’re very nice to receive. You see an employee who does killer work, so you give her a spot bonus of a few thousand dollars, for which she’s thrilled. “That ought to motivate everyone,” you think to yourself.

How so? Every other employee is thinking, “When is it my turn?” And the employee who received the bonus? She’ll continue to work hard, but if she doesn’t get another spot bonus she’ll become grumpy too. Add it all up and you lose more than you win.

Annual incentive programs and employee stock ownership programs, or ESOPs? When structured properly, these are pretty good ideas. They work well because they deliver enough money to be meaningful. They work well because they give employees a stake in the company’s success. And they work well because they mitigate the enervating sense that bonuses are a management perk. (Management perks deliver a simple message: “Managers are better than you are.”)

Most of all, though, annual incentives and ESOPs work because they’re great communication tools. The money isn’t as important as the message, and the message says, “We really mean it when we tell you about the kind of behavior and results we value. You know we mean it because we’re putting our money where our mouths are.”

If you think of money as a communications vehicle you’ll stay on track with spot bonuses and salary increases, too. Present the salary increase as your understanding of the employee’s quality. Deliver a spot bonus privately, and say, “We don’t give out a lot of these. You’ve done a lot to earn it, and your work on the new payroll system is just the most recent example. This is just our small way of saying we appreciate the great work. Thanks.”

Delivering money unfairly demotivates employees as much as anything you can do. Using it to motivate is risky.

But used properly, it’s a great communication tool. After all, money talks.