Leaving typical french play - but not out of theory, the french favors queenside expansionism.

Pressures the d pawn. Skewers the Knight to the queen.

loses a pawn as it does not defend the d5 pawn after the exchange.

I can castle along with white if Be7 on the kingside, but in a traditional face masher white center will be very influential. More risky is the queenside castle, but black has more force facing whites kingside... if I can just shove some pawns at whites kingside later on, whites center may be completely negated...

Typical - greatly enhances king safety.

Vying for space in blacks new playground.

White gets antsy, probably better would have been e5. A pawn push does tickle the gut.

White allows me to centralize my queen, which increases her value. The black knight was of little threat initially, better probably would have been to play Nd4 and centralize behind his powerful pawns.

More space, more force, more influence, more threats, more possibilities. *It may also undermine whites center.

? Out of respect I won't say blunder... but exf5 is better here.