An often seen move

I take it your playing black ? You dont even have to play nge7 you could play a6, Nf6 and several others its your option i would recommend studying the opening !

Thank you, but say if I was in white's position, how could I cram their position?

I used to play this : kinda liked having those knights connected. I guess it depends on your style, but I now think this is a mistake considering the purpose of opening : to develop your pieces and control space on the board. 

You lose one tempo protecting a knight that isn't in immediate danger, when you could make a much more active move : this isn't good, you don't want to lose time at the very beginning, not on a move that isn't necessary.

The light-square bishop is a very important piece for white. Its loss would be worse for him than your double pawns. Besides, only a poor player would just go ahead and take your knight at this stage of the game, without any plan or real gain whatsoever.

So, if it takes, he makes a mistake : you don't need to prevent from this. If he doesn't, then your knight will just stay there, getting in the way of both your dark-square bishop and your queen, increasing the number of moves you'll have to make in order to eventually reach a decent position. If at some point you're even forced to move it, what was the point of putting him here in the first place ?

The bottom line here is that you shouldn't make moves that prevent only one of the lines your opponent could play. You want to have it all covered. Here, if the bishop doesn't take the knight, which he shouldn't do anyhow, you're stuck with a bad position, thus weaker against another attack.