e4 e5 nf3 f6!!??

3. Bc4 is a simple way for white to get +/-.

Ah, but it opens a line for the development of the Black queen's bishop.

It doesn't develop, but it prepares the development of the light squared bishop, so it's not a bad move, but of course not as good as the developing move 2. Nc6 or 2. Nf6.

The problem with 2..f6 is that it doesn't do anything. It is supposed to defend the e5 pawn, but the pawn can just be taken. The only thing it does is weaken your king's position. You could even play 2.. a6 and the pawn is still defended indirectly (3.. Qe7 if 3. Nxe5) and that at least wouldn't weaken the king's position. 2. f6 is just a bad move.

It is a horrible defence!! Once someone played it and didn't get smoked by me. If played accurately it can not be a total disaster. But... Most don't and get killed. It was a opening trap I thought I had discovered until recently realising it is actually a named black defence. Anyone that has a clue has to know it is weak!!

I think you mean +0.6

3...Ne7 is probably the best line for black

Just because an opening requires precise play does not condemn it, it just means it's hard to play - It appears that this opening is fine as long as you play it right.

Who cares about precise play if all it gets you is a terrible position? If I play precisely I'd like to get something good for it lol.

Bobby fischer played it.  Does that tell you anything?

Black can only regain the lost pawn through 3 .. Qe7, but sacrificing time and his Kingside structure. Black will lose more time when white starts chasing the queen with Nc3 or o-o Re1 and a bishop move. Kind of like a scandinavian with a shattered kingside to boot.

THE DAMIANO DEFENCE IS NOT AT ALL BAD. what about 3... Qe7? material will become equal, and the f6 pawn will help support the center, and limit whites knight once it comes back to f3.

3... Qe7 is the only correct way to play. Anything else is pretty much immediately lost, Qe7 recovers the pawn but is too slow and more time will be lost because there are way too many ways to start harassing that black queen. It's like a scandinavian gone horribly wrong.

Not to mention your kingside is permanently weak.  So not only will you be hopelessly behind on development, you have to babysit the permanently weak kingside structure (or try to)

worst opening for Black:

1 e4 e5 2 Qh5 Ke7 3 Qxe5 mate

If I were black though, I'd move the knight on f6 after the white queen takes the rook. And the queen is trapped on several moves I think.

The Queen is actually not trapped. White is winning in that position. That might be a good practical try at some levels, though.

....Gabor explored.