The only use for the concept of ‘past’ is to learn from our mistakes. Otherwise, no point living there anymore, it’s gone. The only use for the future (as a concept) is to make cursory plans, lightly held. Otherwise, no point living there anymore, it hasn’t arrived. Living in the present is where the learning from the past and planning for the future occurs. It’s where Eternity meets existence. That’s all we’ve got folks, we might as well stay HERE NOW.