Being half-hearted about things is not the best way to go through life. It's similarly ineffective to care too much about what other people think -- at least if that means compromising your convictions.

For example, maybe you're living in a house that's bigger than you need, just because you wanted to look good to others. Or maybe you're driving a big gas-guzzler because it's an impressive car, while a little voice is telling you you'd be better off in a hybrid. Heck, caring about looking good is what gets many smokers smoking in the first place.

It's the same in the investing arena. We often chase high-flying stocks because we love the thrill of it, the hope of some outsized returns, and that we can mention to others that yes, we're invested in that. During the years of the growing Internet bubble, many of us piled into stocks we knew little about, not wanting to look dumb by passing them up.

Berkshire Hathaway's (NYSE:BRK-B) Warren Buffett did the opposite. He spent a bunch of years being laughed at for not investing in stocks like Cisco Systems (NASDAQ:CSCO), Yahoo! (NASDAQ:YHOO), and Amazon.com (NASDAQ:AMZN), but he ended up with the last laugh. He's always said he stays within his "circle of competence," sticking to companies he understands -- and whose futures he's fairly certain about.

Another respected investor is Bill Miller, manager of the famous Legg Mason Value Trust (LMVTX) fund. He racked up an incredible record of beating the S&P 500 for 15 years in a row before suffering a few years of losses -- due to some bad calls on financial stocks such as Citigroup (NYSE:C). Many who'd praised him started criticizing. But he stuck with many of the companies he'd believed in, and after a loss of 55% last year, so far this year, he's up a market-beating 30%. His recent top holdings included Sears Holdings (NASDAQ:SHLD) and eBay (NASDAQ:EBAY), both companies with plenty of critics and doubters. Miller seems to be again sticking to his convictions more than trying to look good.

We can and should do the same. If you believe in being greedy when others are fearful and fearful when others are greedy, don't weaken. If you think a sleepy little cement company has great prospects, don't pass it by in favor of today's hottest stock.

Trust in your educated instincts, and keep learning:

Longtime Fool contributor Selena Maranjian owns shares of Berkshire Hathaway and eBay. Amazon.com, Berkshire Hathaway, and eBay are Motley Fool Stock Advisor picks. Sears Holdings and Berkshire Hathaway are current Motley Fool Inside Value selections, while eBay is a former one. The Fool owns shares of Berkshire Hathaway. Try any of our investing newsletters free for 30 days. The Motley Fool is Fools writing for Fools.