Paul Graham, in this essay from 2010, makes a great point on investments (both in terms of money and our use of time):

In most people’s minds, spending money on luxuries sets off alarms that making investments doesn’t. Luxuries seem self-indulgent. And unless you got the money by inheriting it or winning a lottery, you’ve already been thoroughly trained that self-indulgence leads to trouble. Investing bypasses those alarms. You’re not spending the money; you’re just moving it from one asset to another. Which is why people trying to sell you expensive things say “it’s an investment.”

The solution is to develop new alarms. This can be a tricky business, because while the alarms that prevent you from overspending are so basic that they may even be in our DNA, the ones that prevent you from making bad investments have to be learned, and are sometimes fairly counterintuitive.

A few days ago I realized something surprising: the situation with time is much the same as with money. The most dangerous way to lose time is not to spend it having fun, but to spend it doing fake work. When you spend time having fun, you know you’re being self-indulgent. Alarms start to go off fairly quickly. If I woke up one morning and sat down on the sofa and watched TV all day, I’d feel like something was terribly wrong. Just thinking about it makes me wince. I’d start to feel uncomfortable after sitting on a sofa watching TV for 2 hours, let alone a whole day.

And yet I’ve definitely had days when I might as well have sat in front of a TV all day—days at the end of which, if I asked myself what I got done that day, the answer would have been: basically, nothing. I feel bad after these days too, but nothing like as bad as I’d feel if I spent the whole day on the sofa watching TV. If I spent a whole day watching TV I’d feel like I was descending into perdition. But the same alarms don’t go off on the days when I get nothing done, because I’m doing stuff that seems, superficially, like real work. Dealing with email, for example. You do it sitting at a desk. It’s not fun. So it must be work.

With time, as with money, avoiding pleasure is no longer enough to protect you. It probably was enough to protect hunter-gatherers, and perhaps all pre-industrial societies. So nature and nurture combine to make us avoid self-indulgence. But the world has gotten more complicated: the most dangerous traps now are new behaviors that bypass our alarms about self-indulgence by mimicking more virtuous types. And the worst thing is, they’re not even fun.

Do you have days like the ones Paul describes? The day breezes by, and you seem like you’ve accomplished nothing?