Long racing means many individual moments. Never judge them. Observing them is ok- it keeps positive and negative out of the equation and allows you to see the situation for what it is and adjust accordingly or if necessary.
The problem with judging a moment is that it can send you on an upward or downward spiral mentally. Downward spirals are obviously bad because they can lead to complacency and lack of effort. Upward spirals are just as bad because they can lead to unnecessary effort spikes which inevitably catch up with you deeper into a long race. The longer an event is the more likely you will experience events that could be viewed as negative or positive- don’t spend time on the roller coaster of emotion- you’ll be exhausted when you get off.