The ups and downs of the price of a particular stock or the market as a whole. A group of investments that perform the same under market conditions. How you feel about how your money is invested and how much risk you want your investment to be exposed to. Diversification Spreading your investments among the various asset classes to achieve the level of return and risk consistent with your risk tolerance, goals, and preferences. Your personal choices for investments based on your risk tolerance, goals, needs, etc.
All investors have their own feelings about their money.
By understanding your situation you can build a savings and investment plan that will help you meet your goals and let you sleep at night.