Humans have a very uncanny ability to fit correlations into two separate things that have no correlation and explain it very well. Its really hard to stay unbiased when you hold a stake in an asset that you hope to profit from.
We also have a fantastic ability to spot trends in things when they are there.I'll fully admit I am long-term bullish, but that is based on fundamentals. Yes, I hold some coin and hope the price goes up, but it doesn't change the past correlations I outlined.