A lot of older people lost money when persuaded to buy investment products sold to them by their bank, which they didn't really understand. I have every sympathy for them. DD after being mis-sold an endowment policy with her mortgage, has come up with Rule 2 (No 1 being, as janeainsworth said, if it sounds to good to be true, it is too good to be true) Never invest in anything you do not understand. If you have read all the documents and still do not fully understand what you are investing in. Don't
I have very little sympathy for intelligent people who put all their money into get rich quick, high return schemes. For the last ten years DH has regularly been phoned by 'boiler room' fraudsters who, if you listen to them, will try and sell you shares in a company you have never heard of but whose shares, they say, will soar in value in the next year. I have heard people who lost money to these people explaining how pleasant and nice these persuasive people were and it has constantly amazed me that a) they had stayed on the phone long enough to discover this and b) anyone would consider buying something they had never heard of, from someone who cold called them. You wouldn't buy a car, sight unseen, from someone who cold called you, why put your life savings into the share equivalent? To describe such people as 'naïve and trusting' is a kindness to someone we may know or sympathise with but I would use much harsher language for them.