It needs to be interesting

Do everything what we learn should be useful for us?
I believe so. In present days, we got no time for spend it on useless activities. But do we always know what would be useful for us? Do we know it, when we first time hear about something? All those blogs that we are reading, all those books, is there always something useful? Sometimes answer isn't so obvious, sometimes is. Sometimes even happens that we learned something, but life changes and knowledge which was never used before probably never won't be used.
But do we think that was a waste of time? I can answer only for myself, but many times, when everything changed, I didn't regretted what I've learned, even when I knew that knowledge won't be useful for me anymore.

Isn't contradiction? Firstly I wrote, that everything should be useful and then I wrote that I don't regretted time "wasted" on learning things which I don't need at all?

Not entirely.

When I'm starting to learn something new I always assuming that knowledge will be usefull for me in future, either because I have already plan inside my head or it's so interesting, that I will definately somehow use it, it's so cool, that there is no other option.

And this is the point.
We got no time to waste it for useless thing, but whenever we find something interesting, we don't treat time spent on this activity as wasted. We are learning, because we want to and I believe that most of us think that knowledge would be useful one day. Sometimes those assumptions comes true, sometimes not, but it's not so important. The main thing is that we want to learn it, we want to know more about particular topic, we want to dig deeper.

We got families, childrens, work, studies and other really important things to do, but whenever we find something extremaly interesting, we somehow finds time for it.

Why I'm writing all of this?
Through primary school, secondary school, college, universities I met many teachers and professors. And there was a common problem with most of them - they didn't knew what to do to make the subject interesting for us.
I know, that some of us prefer math, some of us prefer history and so on, but as far I remeber there were also great teachers, who taught in the way, that everyone knew whats going on, noone wanted to be absent on the class and there was no problem with bullies, because even they were interested. And those people were teaching different subjects - history, grammar, physic, even knowledge about religions!

I don't want to say, that people who taught me had no knowledge, because it won't be true. To be honest, In my opinion, they are extremaly smart, but I also think that isn't enough. Being a good teacher is not about being really smart (of course it helps), it's more about ability to transfer the knowledge in the way that people who are taught will be interested and will know what it's all about.
They will look for more, they will learn more and they won't think that is waste of time.

And maybe one day, it turns around, that knowledge which they learned are really important and useful for them.