How do you react to the King's Pawn Opening?

Caro-Kann, French, e5, Scandinavian, Petrov, Sicilian, Modern Defense, those are the top moves

I like Petrov a lot

The few time I’ve played e4, I didn’t like playing against the Petroff unless there was a Stafford Gambit. Assuming you play e4, what do you like to play against the Petroff?

c6 or c5, lately I've been playing Caro-Kann more often than Sicilian.

Buddy. The French from my experience is not fighting for a draw. Most of the time, people play the Exchange and play for a drawish position as White which I don't know if you play it but it's very rich from some people. As Black, there is a lot of counterplay after the center is closed with the pawn breaks which after a while will open up for your light-squared bishop to get involved. 

I react with fear and doubt

1...c6 and offer them a draw. Just kidding!

Actually 1.e4 e5 2.Nf3 Nf6 3.Nxe5 Nxe4 is not bad at all, there is no direct punishment, and even getting a meaningful advantage as white is far from being simple. Actually it is vastly superior to sheer rubbish like the Stafford, which has become popular between beginners because a few online clowns are advocating it.

So far I have played it only in blitz games, and I have a very good score as Black.

I watched a game of ai.Hiarcs vs ai.Hiarcs on this position which ended in a draw :

if there was a concrete refutation form the openning it would have been automatically seen and the game could only have ended by a victory for white. 

Caro-Kann recently. It's solid.

For Caro-Kann I see several things that bother me.

a : 1) e4-c6 2) d4-d5 3) e5-Bf5 4) Nc3-e6 5) g4 is far from quiet but it can be fun. (a : is just to say beware of "general ideas" like Caro-Kann is quiet, solid etc.)  

b : 1) e4-c6 2) c4 is embarrasing 

c : 1) e4-c6 2) d4-d5 3) exd5 as often the exchange variant [even if not the best] is the one that can annoy the most I find. On this I found as a parade 3)...Qxd5 which transposes into a defense Scandinavian and the end I think is better to play Scandinavian directly.

I play a: 4)g4 

I play e5

What is wrong with the Panov Attack?

it's hard to say, it's a bit like the alapine scicilienne where at the beginning it looks simple since I tell myself that I'm going to play a position against an isolated pawn where it's enough to block the pawn, exchange the pieces etc. then in practice, white has resources and at the end of the game I'm not satisfied.

Normaly we can't take out the Bf5 for example 1) e4-c6 2) d4-d5 3) exd5-cxd5 4) c4-Nf6 5) Nc3_ 5)...Bf5 6) Qb3  so we tend to lock up the Bishop with 5)...e6 or 5)...dxc4 6) Bxc4 (white has a more pleasant position to play as it has the advantage of space and the open c and e column). 

Interesting. I should take a look into it. Thank you