If you were to spend the next five minutes pushing with all your might against a solid brick wall, would that be time well spent?
Most of you would immediately answer, "No!"
But the correct answer -- as it often turns out to be -- is actually, "It depends."
Specifically, it depends on what you were trying to achieve.
If you were trying to move that wall, you probably wasted five minutes.
But if you were trying to get some isometric exercise, you probably had a very effective workout. (If you don't believe me, try it.)
What you do is only important if it helps you achieve your goals.
That's the reason marketers are taught early on to never evaluate a piece of creative before first reviewing the creative brief; you have to evaluate it based on what the business is trying to achieve (as outlined in the brief).
Ensuring your actions line up with your objectives doesn't only apply to work.
It's a good idea to ask yourself why you're doing anything before you actually do it.
Why am I going for a run? Because I'm trying to be more fit, and running helps with that. Excellent!
Why am I spending time mentoring this student? Because this student has asked for my help, and I want to be the type of person who helps others. Amazing!
Why am I about to watch this television show? Because I need to unwind before bed, and watching some TV helps me do that. Awesome!
Why am I writing this summary report? Because... um... because that's what I think people will want? Less awesome... it would be better to find out if your report-writing is time well spent before you spent that time.
It's said that if you don't know where you're going, any road will take you there.
Spend time knowing where you want to go before you take your first step.
P.S. I once saved myself three days of work when my manager asked me to write a report that would have taken that long for me to write. How? After she asked, I replied, "I can absolutely do that for you if you'd like, but it will take me about three days. A question, though... the Knowledge and Insights team produces a report every month that I think would address 90% of what you're looking to see; can you help me understand what more you need so I can get it for you?" It turns out she didn't know that K&I monthly report existed, and when I showed it to her, she told me it was exactly what she needed and thanked me for my time. This isn't pushing back; I would have been happy to do the report if it was needed, or even wanted. It's simply valuing your time and ensuring it's always well-spent.