TL;DR

Let's have a look at the high-reward activities from the perspective of time passing by. This assumes you do have some goals in life in regards to weight and fitness, social network and money.

Time for self-improvement

This is pretty obvious. In 2015 both me and my friend started some improvement in our lives. I stuck with the changes. He didn't. After a year I was slim, had defined muscles, and he was a fat, lousy fuck again, the type that has unkempt beard and hair (even if he did take care in the past of it, after getting my advice). I went out of my typical mindset of calling him names and looked at the situation objectively.

The truth was, if he ever wanted to do some self-improvement, he had exactly one year less by that time. This is pretty obvious for you, dear reader, but for me - actually experiencing this, seeing his negative progress over one year of time - this was an interesting experience.

Alcohol

I abused alcohol in the past. It also seems obvious: after the party my body needed time to detoxicate. So, I was sleeping or living in some form of a hangover half-life. Time wasted. Obvious.

What is not obvious: time at the party. This is what most of you will overlook. "But how, ex_addict_bro, alcohol makes me a social beast, a master dancer and a great karaoke singer and I can pull Hb8s like mad". Of course you can. Except that your vision of reality is not sober. You are not able to mindfully analyze all those small social quirks, all those connections, all those subtle accents.

By being drunk at a party you're wasting your time that you could use for actually learning how to be more social, how to socialize better. You are wasting your time to see, feel and analyze how well does TRP works in the social setting.

Food

Can I eat this ice-cream? Of course I can. I don't tolerate sugar too well. It makes me sleepy. After eating big I need to sleep for 2-3 hours. Time wasted, perhaps. Could I get fat? Yes, of course I could. Is that a tragedy? Not exactly, I'm not a model. It would just need some more time to exercise and to burn it.

Suddenly I realize I don't have enough time for that ice-cream.

Or, in other words, I can eat it and have the consequences, but I'd rather spent my time differently, to do something more useful.

Debt and video games and everything else

That's the most obvious, I think. Video games - you click a button, something on screen happens, your brain produces dopamine. Time flow continues as usual.

Debt - you don't have money now, but you assume you will have them in the future. So you borrow from the future. As time is money (for us, working people, literally), this is literally borrowing time from the future. So, in the future you have less time.

No more time for this post

If you get the idea, I'm sure you will bring up more examples in the comments.

Also, I am no way affiliated with the author, but "Death Wish" by Steven Chandler is out (Amazon has the details, I'm pretty sure I'm unable to link there). This is the book I got the idea of "borrowing from the future" from.

It was actually funny for me to walk through the mall today and realize I don't have time to eat that ice cream. Or, that I do have time to do anything I want, would I want to spend my time sleeping after over-indulgence of high glycemic index carbohydrates and getting insulin spike? This is a pretty new thought, a pretty new approach for me. I think the change has finally come. I'm looking forward for more.

Summary

Our actions have consequences. For some of them, the consequence is they leave us with less time on our hands. It seems mindful to remember this before actually taking some of those actions.