If a person understands BTC - he won't have shaky hands. Never.
.Hence, investors should utilize dips when they have the chance( not suggesting stressing of investment if they can't afford it )focusing on the price too much will only bring about late investors panic and selling their coins to someone who's ready to get it cheaper
...That's one of the things that makes investor commit mistakes in their journey @focusing on the price always. The effect of steady price watch can cost you errors of bad decision because you would be fluctuating when it comes to staging the right price to buy but if you have a steady flow chart of buying no matter the price then even the big dip that would come after the bull won't scared you infact that would even be a better opportunity to buy more but the fixed thought that covers all the motive is when you are fixated on not selling your coin anytime soon.
I don't agree with your first two line of sentence, saying this is one of the thing that makes investors commit mistakes in their journey @focusing on the price always is a wrong statement rather you would have said that it is one of the thing that makes some investors not to do well in their investment and not investors because you are generalizing it, not all investors are been moved or carried away by what the market present at a particular or given point in time.
However, checking market or monitoring the market can be tempting especially to a newbie that doesn't understand how the market move or works though checking or monitoring the market is not bad but one shouldn't check with the intention to see profit immediately because some investors, after investing they are always checking the market to see if they are on profit or if there investment is making progress this kind of investors are the ones that can easily spoil their investment because of the intention they have.