Financial myths which are untrue

[frozzor]

While I was thinking about finance, it came across to me that maybe a lot of newbies think the wrong way about many things. So maybe you guys could help me make a list of some ideas that many people believe are true but really aren't. Plz correct me if i'm wrong about anything.

I'll start off:
#1 You can save money and live off the interest.
Completely untrue IMO. After taxes you barely beat inflation(if you do). Even with new high yield accounts that give 5%, if you're in the high bracket(like me) you'd only get a little over 3% post-tax. In the long run, using conservative savings and money-market accounts you can't really live off a lump sum because the purchasing power of your money falls. Every time I hear someone say they'd 'live off the 50k interest of 1 million' if they won it, I consider that pretty dumb.

#2 You can't beat the stock market
While most people here seem to believe that investing index funds is the way to go and historically they beat mutual funds, this shouldn't lead to the conclusion that no one can beat the stock market. While it is tough, it is possible for a person to beat the market in the long run. Similar to poker, many people think they're better than they are, and that makes them fish. Also, people should be wary of fund-managers who are more often salesman than actual traders/investors. But there are a handful of people who are quite +EV playing in this game.

#3 Stock market is a zero sum game.
In actuality the stock market is a positive sum game, which has averaged about 10% per year. Options and futures are zero sum markets, but not stocks.