1.e4 e5 f5?! in all openings!

Hello lichess word! I was sitting in my room and I had a funny thought.
When is it "playable" to play the offbeat ....f5 for black, and not only that but when does black become the trickster? and not the tricked!
well here is what I found to be super funny:

1.e4 e5 2.Nf3 f5?? black is just lost.
1.e4 e5 2.Bc4 f5?! black is close to lost.
1.e4 e5 2.Nf3 Nc6 3.Bc4 f5!? black is only worse! the mysteries of life!
1.e4 e5 2.Nf3 Nc6 Bb5 f5 black is close equal.
1. e4 e5 2. Nf3 Nc6 3. Bb5 Bc5 4. c3 f5! Black is close to equal again!

So.... what I have learned is that the better the opening, the better blacks chances are to play f5 without resigning :D
please share your thought! before you post anything not; this is just my opinion with computer help.

Actually, you're not lost after the 2nd move if the computer gives an evaluation of +0,5/+1...

1.e4 e5 2.Nf3 f5 is perfectly playable, it is known as the Latvian Gambit.

1.e4 e5 2.Bc4 f5 seems more dubious, such as 1.e4 e5 2.f4 f5

Well you need to go deeper but if you look at any database with a computer further you go the worse it gets for black.

Also it's common knowledge it's bad.

I'm not saying that the opening is as reliable as some classic lines, but we are not computers and it remains completely playable at club (and even FM/IM) level.
Also, when you play such a line, there is often a disymetry in preparation: the player in white has to guess the moves on the board, when the player in black knows his stuff.

Well maybe sub 2000 fide you can get away with it but otherwise you're just asking for trouble.

Latvian is pretty horrible imo. Have never looked at 3...f5 against 3. Bc4, but against 3. Bb5 its perfectly playable.

Yeah I just think it's funny how the better the opening the better the gambit becomes. xD

The Latvian is already refuted and a losing terrible opening.

The Janisch (e4 e5 Nf3 Nc6 Bb5 f5) is a decent and playable opening, even in top level.

that's what i said lol