My problem with the life force is the Goldilocks problem: it's too much, or it's too little, but it's never just right.
For me, feeling good about life leads immediately to the most persistent, attention-demanding, and unsatisfiable desires. When I'm happy, all I can think about is how I want to start exercising twice as much and get super-fit and buy all new clothes and get a new convertible sports car to drive around in and get a crazy new hairstyle and be a famous philosopher and make lots of extra money and write an amazing novel and always wear the coolest high-heel shoes, always, always.
It's fun but it's exhausting and I think to myself, "Well. Wouldn't it be nice to be a little less in the way of wanting things? To want, you know, a more modest list of things?
And then I get my wish: the intensity fades, the sports car seems silly; the new hairstyle seems impractical; the novel-writing seems ridiculous. I resolve to spend my time on sensible pursuits, to enjoy the good things in life in moderation.
You'd think this would be an improvement, but it never is, because the only thing worse than wanting things is not wanting things. As soon as I don't have all these crazy desires, I'm back on the sofa, thinking to myself, "What is the point of all this, exactly? To muddle through and then get weak and frail and then die?" Boy is that worse than daydreaming about impossible things you'll never have.
It's either the Papa bear of too much, or the Mama bear of too little, but clearly if there's not going to be any "just right," I gotta choose "too much" 10 times out of 10.
When you think about it this way, our American extreme consumer culture seems less strange and surprising. It's not just the shopping that allows us to avoid thinking about death, even the not-shopping allows us to avoid thinking about death. As long as it's not-shopping together with a lot of intense, regretful longing.