Equilibrium question:

[Lycan]

Can someone succintly explain to me why Le chatellier's principle holds?

I.e. Why does a reaction at equilibrium try to oppose any changes to this equilibrium?

Please do not just say something along the lines of: 'it needs to keep the same K value'.

It's been bugging me for a while, help is much appreciated.

[Collin Li]

It comes from thermodynamics. You need to understand entropy -- not covered in VCE. There would be quite a bit of pre-learning required to do this. Le Chatelier's principle comes out of the maths when solving for thermodynamic equilibrium.