If someone buy a coin at a certain rate and after which the coin drops, that's shouldn't bother you though it depends on the coin you bought cause if it is a shit or memecoin then it is something to be worry about because most of those coin whenever they drop they don't appreciate easily and most will never appreciate again but if it is Bitcoin you invest in there's nothing to worry about cause even if it drops it will definitely appreciate. However, when buying shit or memecoin you ought to be very careful before you dive into it cause it can be annoying at times and sometimes sweet when your analysis is being done correctly.
The discussion here is Bitcoin, so it could be nice we retain that world to avoid bringing too many variables into the discussion. Like you already deflated into memcoins and shitcoins which I think are not ideal to discuss in this section of the forum and if we persist, people might assume that anything that has coin attached to it is worth paying attention to.
Anyone who invest in Bitcoin must understand that price does not continue to rise without corrections, this is how the market is design because there will always be buying and selling and whenever there are more people selling within a time frame, they there is excess supply which will make price to drop and continue in that direction until something changes and demand surpass supply again which will in turn lead to the continuation of the upward movement. The time that market retraces is not a time to panic but a time to buy more and profit from the market when it reverses to the upside.
Many people fail to appreciate the fact that retracement is truly an opportunity for more discounted buys. For instance, assuming Bitcoin is rising the suddenly it hit a major resistance and fell from let's say $70k to $63k. Now an investor with $10k to invest in Bitoin lump sum might have two scenarios. First is if he buys at $70k, he will get $10k worth of Bitcoin as 0.143BTC but if he bought at $63k he will get 0.159BTC. Under this arrangement, the investors would have gained 0.159 - 0.143 = 0.016BTC. Now assuming Bitcoin reverses and hit $75k, he would have made dollar gain of 0.016X75,000 = $1.2k cool cash. This example is just to demonstrate the opportunities retracement in price offers and not to discourage anyone from buying but to wait for major retracement. There could still be other methods of investing the $10k that would have yielded different and sometimes better result.