Here are 67 reasons why people did not invest in the stock market:

Fundstück

1934 Depression
1935 Spanish Civil War
1936 Economy Still Struggling
1937 Recession
1938 War Clouds Gather
1939 War in Europe
1940 France Falls
1941 Pearl Harbor
1942 Wartime Price Controls
1943 Industry Mobilizes
1944 Consumer Goods Shortages
1945 Post-war Recession Predicted
1946 Dow Tops 200 – Market Too High
1947 Cold War Begins
1948 Berlin Blockade
1949 Russia Explodes A-Bomb
1950 Korean War
1951 Excess Profits Tax
1952 U.S. Seizes Steel Mills
1953 Russia Explodes H-Bomb
1954 Dow Tops 300 – Market Too High
1955 Eisenhower Illness
1956 Suez Crises
1957 Russia Launches Sputnik
1958 Recession
1959 Castro Seizes Power in Cuba
1960 Russia Downs U-2 Plane
1961 Berlin Wall Erected
1962 Cuban Missile Crisis
1963 Kennedy Assassinated
1964 Gulf of Tonkin
1965 Civil Rights Marches
1966 Vietnam War Escalates
1967 Newark Race Riots
1968 USS Pueblo Seized
1969 Money Tightens-Markets Fall
1970 Cambodia Invaded-Vietnam War Spreads
1971 Wage Price Freeze
1972 Largest U.S. Trade Deficit Ever
1973 Energy Crises
1974 Steepest Market Drop in Four Decades
1975 Clouded Economic Prospects
1976 Economic Recovery Slows
1977 Market Slumps
1978 Interest Rates Rise
1979 Oil Prices Skyrocket
1980 Interest Rates Ar At All-Time High
1981 Steep Recession Begins
1982 Worst Recession in 40 Years
1983 Market Hits New High
1984 Recorded Federal Deficits
1985 Economic Growth Slows
1986 Dow Nears 2000
1987 Record-Setting Market Decline
1988 Election Year
1989 October „Mini-Crash“
1990 Persian Gulf Crisis
1991 Communism Tumbles with the Berlin Wall
1992 Global Recession
1993 Health Care Reform
1994 Fed Raises Interest Rates Six Times
1995 Dow Tops 5000
1996 Dow Tops 6400
1997 Dow Drops 554 Points in One Day
1998 Asian Flu
1999 Y2K Scare
2000 Technology Bubble Bursts

And One Good reason Why You Should: $10,000 invested in the Stock Market (Standard & Poors 400 Index) in January of 1934 would have been worth over $20,559,704 in December of 2000.
Year after year, people think of reasons why they should not invest in the market. And year after year, the market outperforms virtually all other investment opportunities.