Why do you think that everyone thinks the gerund is a complicated aspect of the English grammar? I am glad to hear that it's of no problem to you and hope that you will share your knowledge to help other people. I wish you good luck with studying English!

I don't think people have difficulty adding "ing" to the end of a verb. I think they have difficulty understanding WHEN to add it... .

Yes, it's not.

Frankly, I do not quite understand it! Tell me, gerund is simply adding the end of ING?

In Russia, most people in the study of English are afraid of the topic, thinking that it's hard to understand...