Feeling negative thoughts vs. creating a positive intentional model

How do you decide whether to sit with your negative thoughts and experience negative emotions rather than creating a new intentional model with more positive thoughts and improved emotions? I understand the concept of allowing truly negative emotions like mourning a loss of someone, but how about something more benign, like tasks you need to complete but don’t like to. Should you accept that you don’t like those tasks and get through them while feeling negative emotion or should you try to find a more positive model? Is there a general way to differentiate when be with emotions vs. attempt your best to swap them out?