Depends on whether you want to learn or impress someone, and who, and why. If you want to learn, go for it, all the established courses, long and short, free and paid. Respect you have to earn, usually with action, and that comes after you education. Clicking through multiple choice tests until the checkmark turns green isn't really heroic.

Though making the effort to educate yourself is a respectful act. Demonstrates strength of will.

Some people like to be perceived as if they were mysterious genii who know it all, somehow, and that it makes them look weak if they make an effort. You be a fool trying to impress them in any way, shape or form, you'll lose the respect for yourself.