Being a passive-aggressive investor doesn't sound too healthy, does it? Passive-aggressive people generally resist doing something they don't like in a quiet, sometimes sneaky way -- like taking so long to get ready for a party they don't want to attend that it's almost over by the time they get there.

Bad passive-aggression
That same kind of sulky resistance often crops up in investing. Too many people feel intimidated or overwhelmed by the thought of opening a brokerage account or an IRA that they put it off indefinitely. Alas, by doing so, they lose out on way too much of the performance those investments could have delivered for them.

For example, if you invested $5,000 in a stock, and it grew at just 6% on average each year, you'd end up with almost $21,500 after 25 years. Cut that down to 10 years invested, after 15 years of procrastination, and you'll end up with just $9,000.

Sadly, you might have earned even more than that, since stocks have historically averaged more than a 6% return over long periods. Look at how your money might have grown in these familiar stocks over the long haul:

Company

10-year avg. annual growth rate

In 25 years, $5,000 would become...

Target (NYSE:TGT)

7.3%

$29,100

Norfolk Southern (NYSE:NSC)

9.3%

$46,100

AFLAC (NYSE:AFL)

9.3%

$46,100

United Technologies (NYSE:UTX)

9.8%

$51,700

Data: Yahoo! Finance.

As the table above shows, both the amount of time your money's invested, and the growth rate it achieves, can make a huge difference in your ultimate gains.

What's the matter?
If the passive-aggressiveness described above seems a little too familiar, ask yourself why you're hitting the snooze button on your financial future. If you lack confidence, or feel too unprepared, your remedy is easier than you think. There are plenty of great, easy-to-read investing guides out there to get you up to speed, including our own classic, The Motley Fool Investment Guide, and our upcoming The Motley Fool Million Dollar Portfolio. Investing isn't rocket science -- even though a whole industry on Wall Street gets rich by making you think it is.

Good passive-aggression
Passive-aggressive investing can definitely hurt your returns -- but combining passive investing with aggressive investiong may actually help them.

Passive investing, which involves placing your money in no-brainer index funds to automatically match the market's average return, is all that most people really need. Once you sign up for a broad-market fund, and set up regular payments, it requires almost no effort.

You can juice those simple returns with an added shot of aggressive investing, by reserving a slice of your savings for investments with the potential to wallop the market average. Here are a few well-known names whose historical returns have put Wall Street to shame:

Company

10-year avg. annual growth rate

In 25 years, $5,000 would become...

MEMC Electronic Materials (NYSE:WFR)

9.1%

$44,100

Oracle (NASDAQ:ORCL)

13.9%

$129,400

Suncor Energy (NYSE:SU)

18.6%

$355,700

Data: Morningstar.com.

Not every stock or fund you single out will become a home run, but even a few successes can make a big difference in your financial future. When it comes to investing, that's the right way to be passive-aggressive.