it's funny that some persons will wait for moments when they see bitcoin price going up before the thought to invest in bitcoin comes to there mind and like you rightly pointed out, bitcoin price can go up and then up, up and then down, down and then down and so on. so you can't just predict that because it is going up now , this is absolutely the time to invest into bitcoin and when you see the price going down you retreat from your plan on making the investment. It means that if you even successfully make the investment, you can't hodl your bitcoin because in the event of any fluctuation in price, you will let go of your investment.
Real investors sees the prospect of bitcoin and invest a certain amount and leave it for quality amount of time while he monitor the price without getting seriously moved by any fluctuations in price that comes along the way.
When bitcoin prices are high, anxiety and fear of missing out usually lead some people to consider investing in the bitcoin. They are motivated by the belief that if they invest now while bitcoin is rising, it will continue to increase and they will profit from it without considering the possibility that the crypto market could quickly go from being sweet to bad.
Instead of focusing solely on the current price, whether it is high or low, every crypto investor should set a long-term price target that will help them determine when to purchase and when to sell for a profit.
Oh! this is a bad approach to invest in Bitcoin. People who rush into buying Bitcoin when the price starts rising is endangering his/her investments. Because he is tempted to go all in, after considering that they would miss out and the idea is that at that current price, he feels it is the lowest price and the way the price is rising he is expecting 20x 100x or more. That user has been deceived by the volatile movement of Bitcoin. Because the same speed it uses to rise it can use that same speed to go lower.
If you buy a large amount when it is on the rise and you get some X profits over a short time, it may seem like a wise decision. However, when you look at the growth over the year you realize it was just some fractions of the overall poential of Bitcoin. The real deal remains when you continue to hold for long. At times it depends on your risk tolerance that a person chooses to buy with anxiety, but I have found the most relaxing path is to put some income in weekly or bi-weekly. You can also buy a bit more when a dip presents itself as a good opportunity. This way, you view dips as chances for growth rather than a thinking it is a wrecking moment.