Is 1-Page going bust?, page-164

I'm sure you understand the stock market quite well

Pricing on a stock, is meant to be very rational, but usually is not, either over-optimistic or undervalued at one point, "fair value/price" is only last for "now/second".
There is quite understandable as the market participants are Human beings, we all have own interpretation of what we have observed and it has been changing every second as things are progressing. Also, positive news lead to believe more positive; vice versa.

I always lower my expectation so that there would be less change to get disappointed.