I want to learn only songs I like, why should I play all those exercises?
Whatever you do in your life, you should like the way you do it. Therefore, playing exactly what you like is very important. Otherwise, why play? However, to play in such a way that pleases nobody, even yourself, is probably very torturous and definitely will not bring any joy to you.
The way you sound while playing depends on many factors. But just technically good playing [здесь ссылка на наши статьи по хорошей игре] depends on the level of your technique. Nobody can achieve a good level of technique by just playing favorite melodies. They will not sound better just because of multiple repetitions one can make. After all, he will make mistakes in the same places and would not even pay attention to that, since he will be focused on a melody, which should not sound torn apart, but not on a technical execution.
Therefore, no matter how talented the person is, he has to work on all the techniques for a long enough time.
The most correct way to achieve that is by playing technical exercises and études.
I have got a very big experience not only as a musician and instrumentalist but also as a teacher. The outcome of that experience is my observation of playing people of a completely different level. Starting from the most primitive up to the highest. Everyone without any exception has shown the same thing. When I was giving them tasks, in particular technical exercises, all of them marked a strong improvement in technique. It was reflected in their performance of the compositions they have played. Even on those occasions when I was extremely dissatisfied listening to their playing of technical exercises that they prepared for a certain amount of time.
Also, I have got observations of the people who categorically refused to play technical exercises. Usually, it is those people who mind of themselves a lot. There are several reasons for that, but the most frequent is the fact that they became famous. Having got many records, concerts, and an army of fans, those people did not perceive music adequately. And in particular its execution. Playing for decades, they did not get better at all. And that did not bother them at all. And if they sometimes doubted about their sound, they immediately rushed in search of other instruments, amplifiers, effects, etc. or lashed out at a sound engineer who, in their opinion, incorrectly recorded or mixed them.
It is worth noting that for centuries people have been playing technical exercises to improve technique, and études were even isolated as a separate genre. There is no other way for technique improvement.
Therefore, if you want to play your favorite songs so well that it could bring joy to yourself, you will have to play a lot of technical exercises.
But everyone decides for himself, what level he requires. If you are satisfied with the primitive strumming, then you do not have to play any technical exercises.
