People who fear the dip are mainly those who invest more than they can afford to lose or people who fail to invest their discretionary income and invest money they have need for later that's why it eats them up when there is a dip.
Sometimes that is not the case, there are those who actually invested with what they could afford to lose but as humans there is this spirit of fear and anxiety when the price is falling, even if you have confidence that the price will rise again but in your inner mind you are already feeling fear so it's normal but we just don't need to be too emotional when the market price is falling. Even when you invest with a discretionary income, there will still be fears when the price is DIPPING especially for someone who manage to carve out a discretionary income to invest. Another thing that causes fear and panic is just poverty mentality because i don't think that someone who is very rich will really have that time to be monitoring the market to know when the price is dipping or not, they just invest and allow their investment to grow but for someone who is still managing to source out money to invest, no matter how small the amount he invested could be but he will find it difficult to get his mind off his investment.