French Adance question

Almost all the games I've seen it has Nge7, then that knight goes to g6. I've been playing that knight to f5 to help fight for d4. Is this a bad move? If it's playable why isn't it seen on higher levels? Maybe I just haven't seen it lol

How about posting the exact move order you're talking about? Preferably in an interactive diagram to make it easier for anyone responding to analyze and comment on 

What about the minuet or the tango?

it's definitely not a bad move. i pretty much always play nh6 then nf5 (maybe after exchanging pawns on d4).

It's a good move and a normal plan. Especially effective is the line where White feels he is tough/desperate enough to play g2-g4 to get rid of the Knight - compromising his Kingside severely in the process.

nf5 is a normal square for the knight to go to. It functions well with the c5 pawn--both hitting the base of white's pawn chain: the d4 pawn after c5xd4

Another possibility if you play Nh6 instead of putting that knight on e7 is that you can play f6, then Nf7. Depending on the situation, that's sometimes worth doing.