Life In 19x19

That's enlightening! I had not considered the seki.
Thank you all for the help.

Hello everyone. In a L&D problem appearing in the app "Tsumego Pro" of Android the following position is presented (black to play):

$$c Initial Position.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X X X . . . . . . . . . . . . . . |
$$ | . O O ...

Thank you EdLee. I guess that relying too much on joseki makes one insecure when the opponent deviates from it. For curiosity, in the actual game I replied as in the last diagram, turning to the center.

Hello everyone, I am a novice to the game and recently I played a game where my opponent answered an approach to the 4-4 point with an attachment that is the beginning of a joseki:

$$W
$$------------------
$$ . . . . . . . . . . .|
$$ . . . . . . . . . . .|
$$ . . . . . . . . . . .|
$$ . . . . . 8 ...