I like to do everything for myself. vs I like to do everything by myself.

[Pooh]

What the difference between the three below?

1. I like to do everything for myself.

2. I like to do everything by myself.

3. I like to do everything myself.

[Morteza]

Hi,
"For myself" means not for anybody else.
"By myself" means either alone or without anybody's help.
But "myself" here is used in an emphatic way,not in a reflexive role.
"I myself like to... ." is also correct.
Best wishes,
Morteza

[Pooh]

Hi Morteza, thank you for your help however
I found a sentence in my English text book that makes me puzzeled
about the meaning.

Here it is;

"He was an adventurous boy, he always wanted to do things for himself, and never wanted to imitate others."

In this context, I think that "for himself" means "alone or without anybody's help".
Therefore, now I am not sure the difference between "by" and "for".