Optimism bias is the natural tendency to overestimate the likeliness of positive outcomes and underestimate negative ones.
Pessimism bias, (also known as negativity bias), draws our attention away from positive circumstances and causes us to weigh negative stimuli more heavily.
While adapting to adverse scenarios works well for our survivability, we can also adjust to pleasant things we enjoy. Over time, things that were once exciting and new become familiar.
The sunk cost fallacy describes the human tendency to keep doing something we have started, even if it isn’t working out.