My worst decision on bitcoin when i bought bitcoin on high price then a couple of hours the price went down and as a result i panic and sell it even i will lose a lot of investment. That's a newbie mistake from the past and it happens long time ago but now i learn a lot from that.
I think nobody knows when bitcoin prices will go down. So it's a natural thing when you buy and then the price goes down. As is the case today. Many people are losing because the price drops very quickly