if u are a trader, u will be tempted to make profit and invest in some shares (which u may select thro the rumours going around). if market falls suddenly, u will be left with papers (shares of no value) only. whereas, if u are a investor, u will tend to invest in companies with good fundamentals. hence, even if market falls, in the long run, u will stand to gain. hence in the long run, investing is the best. may be in the short run, trading may fetch u. but unless u take the profit out, u will be left with junk only