Introductions

Can a person be perfect? The answer is no. Everyone has his own advantages and disadvantages. So, from my point of view, there’s something that teachers can learn from students.
Asking a question to start with is a dangerous tactic with your reader. Will your reader have the same answer as you? Maybe not! In this specific case, there is not a lot gained from the question.
Don’t start too far from the topic. Make a general statement, in this case, about teaching and learning and then get to your point.
“my point of view” is clear as you wrote it and signed it.
There is no doubt that the relationship between teachers and students are [is] teaching and studying. However, in some situation [s], teachers also can [also] learn a lot from students in some aspects: general knowledge, fresh things [ideas], and attitude for [towards] life.
This introduction is definitely stronger as it starts much closer to the actual topic. Remember that the reader has already read your title, so is ready, generally, to read on your chosen topic. Use of a contrast transition is a good way to bring the focus closer. In this case, the writer has given the “list of three” approach.
Sometimes, people think the best things in life are free. I have three reasons which make me to [omit-to] disagree with that [this] statement. These three reason[s] are: [colons cannot follow “to be”; instead, use a comma or nothing] [the] value of things, time, and satisfaction.
This introduction is very similar to the previous one. It is clear enough, though the “reasons” are a bit difficult to guess exactly.
Conclusions:
As I have explained [maybe ok; maybe not], I think that free things in life are not the best. Therefore, people should pay for it [things]. In order to be satisfy [satisfied] you have to spend time [,] also. If your thinking is that free things are the best, allow me to say, No way!
If you begin with the three part approach, probably you should end with the same approach. This conclusion does have a very nice final sentence, ending as it does on “No way!” And perhaps, the writer should have used the quotation marks for emphasis.
Teaching is really hard work. It requires [a teacher] to give out a lot of energy, as well is [being] very interesting and creative. Thus, [a] teacher is getting stronger, more intelligent and experienced all the time. [In any case,] if students return this energy [back] over [with] their new knowledge and respective attitude, teachers would feel a great satisfaction from their job well done.
The thesis is not in the first sentence; instead, it occurs in the second and third. Avoid this! The final sentence is a good “predictor” style sentence and a useful way to end many kinds of essays.
Being free in life is the best thing, indeed. We can not only enjoy selecting work[s] we like the most, contributing to our society, we also can enjoy free time exercising [our] bodies. Freedom will be beneficial to everybody!
Exclamation marks are a bit tricky! Avoid them, usually, and use them sparingly. Never use more than one.
Topic Sentences:
We can engage in the work we like the most under the status of freedom. [if we are free] (body 1)
Finally, teachers also can learn a lot from their students’ attitude[s]. (body 3)
Standing at the edge of the knowledge ocean, what do you want to do? (body 2)
Beautiful, but can you guess what topic this is? Don’t go overboard.
In a similar way, teachers are exposed to new cultures. (body 2)
Transition is clear from body 1 to 2 without using many words.
Concluding Sentences:
In other words, they teach better because they learn how to teach better from their students.
The use of “in other words” is a useful concluding technique.
The love is an unfinished [unquenchable; infinite; or?] resource of human warmth, and cannot be stolen, because it is a free thing.
Lovely sentence!
So, the teachers can learn to be devoted, to have a strong will, and [how] to be reliable from their students.
In this case, “so” is used to mean “therefore” and so does not indicate a failure to use it as a conjunction.