Which is worse, losing money on an investment OR losing opportunity on an investment?

losing OPPORTUNITY on an investment.

Years ago, my Dad bought a 'computer'. It ran on an operating system called TRSDOS.  And one day he brought home a New operating system. Took a look at it and said-nah-aint going to happen. The name of the New operating system was MSDOS. 

Losing money by far. Conservative investments have lower risks, and usually pay off in the end. Just don't be TOO conservative.

For me, it depends on the risk and how smart an investment was to start with.  If I missed investing a large portion of my savings in a long shot start up which happened to be the next Tesla I'm not so upset.  If I left my money in savings at basically 0% interest (thus losing to inflation) instead of putting it in a conservative index fund, then I'm mad because I was stupid.

Losing money on an investment is worse.

As one wise man once said "return of investment is more important than return on investment."

Remember you can make 100% any number of times but you can only lose 100% once before you have to start over.

I am not saying that you should never risk losing money on an investment. Making higher returns requires risking losing money.

RULE #1

Never lose money

Losing money is bad but opportunity's come around all the time .