The move at 1 is naughty and should be at a.

Click Here To Show Diagram Code

[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . O . . . . . |
$$ | . . X X . . . . . , . . . . . O . . . |
$$ | . . O X O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . a O . . . . . . . . . . |
$$ | . . . X . . O . X O . . . . . , . . . |
$$ | . . . . . . . . X 1 . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X X . . . . . , . . . . . O . . . |
$$ | . O O O X X X X . . . . . . . . . . . |
$$ | . . . . O O O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This (expected) exchange is bad for black and makes the mediocre move 1 great again.

Click Here To Show Diagram Code

[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . O . . . . . |
$$ | . . X X . . . . . , . . . . . O . . . |
$$ | . . O X O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . 2 O . . . . . . . . . . |
$$ | . . . X . . O . X O . . . . . , . . . |
$$ | . . . . . . . . X 1 . . . . . . . . . |
$$ | . . . . . . . . 3 . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X X . . . . . , . . . . . O . . . |
$$ | . O O O X X X X . . . . . . . . . . . |
$$ | . . . . O O O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Black should just extend to punish white for its cheeky move.

Click Here To Show Diagram Code

[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . O . . . . . |
$$ | . . X X . . . . . , . . . . . O . . . |
$$ | . . O X O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . O . . . . . . . . . . |
$$ | . . . X . . O . X O . . . . . , . . . |
$$ | . . . . . . . . X 1 . . . . . . . . . |
$$ | . . . . . . . . 2 . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X X . . . . . , . . . . . O . . . |
$$ | . O O O X X X X . . . . . . . . . . . |
$$ | . . . . O O O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I often can not resist the temptation for moves like this white 1 . Especially because they are often successfull against my low dan opponents. Risk and reward are quite attractivly balanced in this case in my opinion.

I do not like my opponents to play this kind of trick games with me, and this is one of my motivations to improve.

Why is it an overplay? Because it leaves behind two cutting points and white won't be able to defend both?

I don't understand why move 1 is bad and neither do I understand why extending is a punishment. Both the push and the extension look pretty normal to me.

Seems I am getting stronger step by step

I could give you some english language explanations. But I would make them up in hindsight. It feels like explaining art, a feat I was never good at.

But if you insist:

How about: Pushing from behind is not good.

But to be truthful. Move 1 deemed me naughty during play, and all my AI teachers agreed during analyzing.

Now duck and cover, the flat earthers are coming

I think "pushing from behind is bad" is a good proverb in general, but there is always an "unless" attached to such proverbs. If the opponent can block in sente, it can be neccessary to push from behind to make blocking gote. And AI tend to to push from behind even more for good measure. Also, an extra push may overconcentrate your opponent's potential and expand your own (which applies to this position I feel). So I'm not entirely convinced by this proverb quote in itself.

I may check this position later with an AI to see the huge drop in white's winrate from the push, but I will be curious for the AI's variations to clarify why pushing from behind is a bad idea in this position.

Actually I would say that one thing I have learnt from bots is that pushing from behind (often in centre fights) is actually quite often good and better than jumping ahead with the knights move. This is because by taking a liberty it is actually sente (if they tenuki the hane is a powerful local shape) whereas it's easier to tenuki the knight move as the cap following that is strategically nice but not so powerful in terms of local fighting shape, and also the knight move leaves a cut or peep. The pushing often builds a miai in that you are trying to strengthen one group sufficiently in sente to them take another good point, so you want the strong hane as follow up if they grab that point first.

P.S. As an example, I checked the last game in my LZ on Fox thread, and indeed there's an example, moves 30-34 are pushing from behind because you want to strengthen group in sente by threatening a powerful followup and then grab the important s6 reverse sente. Though actually LZ was black there and the human or other bot I don't recall was white, but once the slight mistake of 28 is made LZ agrees with white's pushing.

So "pushing from behind", it is probably not. I said I am bad at this game (explaining go).