A negative thought is just a thought, it's not like you need to actively not take care of real life things or errands. But if you find yourself thinking about death, or about how much your childhood sucked, or that you're good for nothing, you don't need to address anything about those thoughts.

The least time you spend on them the better, nothing good comes from dwelling.

I can't understand people that want to re-live or push through some negative thoughts "because it'll get better eventually". To me it seems like you're just making yourself numb, and it's got to be at the expense or something. You become so beaten down from them they don't hurt you anymore. I'd rather just not think about bad stuff, they come my away and I go away from them and I get to keep my "mental innocence". Why go through a long road when there's an immediate escape hatch?

Said in a similar way, I could prepare for bad things to come. I know my parents will die. Should I think about that non-stop and feel sad everyday I do it just so I'll feel less sad when they die? Sounds ridiculous.

I have zero desire to "understand" why some thoughts come sometimes, I just want to move past them as fast as possible.