that's why people who have been in crypto for a long time, especially people on this forum, often suggest investing if you are ready to lose and at least use money that will not be used in the near future. because what I feel so far is as you say. The market is very unstable and especially for December and January now and indeed we must accept this and remain calm so that what we do is not wrong when the market is like this.
the market may be hot and prices continue to fluctuate but we must not get carried away and must be level-headed in determining actions
That advice applies to all kind of investments and not only to bitcoin, after all it is easy to think that we are not going to need the money that we invest in it, but life is full of surprises which means that just at the worst possible time when the market is hitting the bottom is when we need the money, this is why it is important have several saving funds so we do not have to touch our investment at the worst possible time, but unfortunately this is an advice very few people follow, and they eventually pay the consequences of those mistakes.
It's true that this all leads to everything that we invest in and not only Crypto but because here we are only discussing Crypto so I narrow it down to be more specific but indeed I do not deny that this is an action taken for all who invest everywhere not only for cryptos.
Now this is the problem, why do we have to do it with money that is really not really used and ready to lose because we will not know about life, sometimes the need comes suddenly and cannot be predicted.
So why is this not done too much, because many of us are still naive and always hope that profits will always occur so we don't predict a market that is indeed volatile.