I really think that what is worth is living the present as if there was no tomorrow, who knows?
I agree, with one caveat. While I think we should live well in the present, that doesn't mean we shouldn't plan and work for the future. The reality is that while we don't know what the next moment holds, the average predicts we will likely live til we are 80 something. I know people who are mid-40s like myself and plan nothing - but they will probably live the last 30 years of their life struggling in many ways. It is a hard life.
As you say, the past can come back to haunt us :)
Of course one must be as much prepared for the future as posible. I'm not, in any way, talking about living a crazy life but more about being prepared to change our plans unexpectedly.
It's more like: "don't miss the present by sticking todo much to the past or the future"... they actually don't exist.