Vanguard Group, the world’s biggest provider of index-tracking products, hauled in $216 billion from investors in 2014. It was the greatest amount of inflows a fund family has ever received in a calendar year, according to the Wall Street Journal.

For comparison’s sake, Dimensional Fund Advisors enjoyed the second-best inflows in 2014 at just $26.6 billion — a mere 12% of what Vanguard hauled in.

What does this tell us about the psyche of the modern-day investor?

Well, a couple things.

#1: Vanguard’s success tells us that the modern-day investor is lazy.

One of the basic concepts behind fund investing in general is that the less trading you do as an individual, the less fees you rack up. Every little bit counts, too — compounding returns over the long haul mean that even a few dollars today can add up to thousands lost in opportunity cost down the road.

Vanguard founder Jack Bogle believed passionately in the concept of a particularly inexpensive version of fund investing called “index investing,” or “passive investing.” With index investing, rather than active managers to pick stocks for you, you instead invest in a fund that merely tracks a particular index. For instance, Vanguard offers the Vanguard 500 Index Fund Investor Class (MUTF:VFINX), which allows investors to simply hold the stocks of the S&P 500 and track its performance over time.

Vanguard funds, led by a cadre of such index funds, apparently appealed to investors last year, as evidenced by the $216 billion in inflows in 2014.

But in general, 2014 was very good for mutual funds — BlackRock mutual funds also witnessed record inflows last year, and in the 12 months ended Sept. 30, U.S. mutual funds saw nearly $330 billion of net inflows.

Funds, active or passive, were very popular in 2014, and that points to a lazy investor.

#2: Vanguard’s Success Tells us That Modern Investors Are Smart

It makes a lot of sense to buy and hold index funds — and Vanguard index funds in particular — simply because they’re not just typically cheaper than similar actively managed funds, but they often perform better too.

Index funds are cheaper because they simply use a computer to properly manage the fund so its holdings mimic those of the fund’s underlying index. And it’s a lot cheaper to run a computer than it is pay mutual fund managers (and their staffers) to pick the stocks.

Moreover, index funds don’t have any “manager risk,” which means there’s no pesky human at the wheel, guided by emotions and rife with potential for error.

In fact, active funds consistently lose to passively managed funds — and the indices they are designed to beat. In 2014, a whopping 74% of active stock funds underperformed their benchmark indices. Yowza.

The praise for index funds — which take stock picking off the board — might sound somewhat traitorous coming from a financial journalist. After all, I write about stock picks on a daily basis, and I even own both stocks and options in my personal accounts.

Still, I — and many others, judging by the $216 billion influx Vanguard saw last year — maintain that low-cost, passive index funds are one of the best ways for the average individual investor to play the stock market.

But don’t take it from me. Warren Buffett, who was the fourth-richest person in the world on the Forbes list in 2014, has repeatedly advised individual investors to use index funds. He even told Berkshire Hathaway Inc. (NYSE:BRK.B) shareholders that 90% of the money he leaves to his wife should be put in index funds. (Vanguard index funds, specifically.)

Buffett wants his dearly beloved to stash her cash in the Vanguard 500 Index Fund Admiral Class (MUTF:VFIAX) when he passes.

With an annual expense ratio of 0.05%, it’s hard to argue with him. See, once you do the math, you start to understand just how great Vanguard’s truly low-cost funds are.

If you invest $50,000 for 30 years, and assume a 6% annual rate of return (a conservative assumption for the stock market), the difference between Vanguard’s average expense ratio of 0.19% and the industry average expense ratio of 1.08% is drastic: You would save $63,915 going with Vanguard, or 127.8% of your initial investment, over 30 years.

The lazy portfolio starts to look like the smart portfolio pretty quickly.

John Divine holds no positions in any of the stocks mentioned, although he does hold Vanguard index funds in his retirement accounts. You can follow him on Twitter @divinebizkid.