NEW YORK ( TheStreet) -- Investors need to believe in something and show the confidence to stick with those beliefs no matter how the markets may gyrate, Jim Cramer said on the "Mad Money" on Monday. He said investors must have conviction and then outlined a few long-term trends that investors should cling to for the next several years. Cramer said he always values flexibility and bring opportunistic in with stocks, but without a world view, a long-term picture of the world, it's just too easy for investors to get shaken out when the next big market correction is upon us. That's why these long-term themes are so important. Investors can use them for years to come.