I believe you are in the market long enough to understand it. See your account's activity point, I knew you have been in this market some years already.
"Buy the rumor, sell the news".
"Being greedy when others are fearful; being fearful when others are greedy".
These above statements are always true in all markets from stocks, gold to Bitcoin and cryptocurrency markets.
This chart of
Psychology of market cycles is true for all markets.
Obviously those type of things do look like they are quite common and happens all the time but that doesn't mean that we are going to be right at all times, we are going to end up with a much better result if we just calm down and make slow movements.
Most people rush into everything that is even a little bit hyped, like going for those stupid meme projects that will worth zero soon enough, most of them already do, and that is not really explained in a greed or fear index, it is not the same thing and should not be considered anything similar to what we have with bitcoin. So while you are right that in bitcoins case that can be true, but we can't really say that it is true for ALL crypto currencies, only the top ranked ones.