For Better or For Worse

You ask about this attitude?
You'll not like the response so I refuse.
You didn't notice it's not me who's changed?
Things aren't what they used to be.
Externally the change is me,
But I'm talking about your personality.
So listen up just like the good ol' days,
Back when things like this would be a phase,
You're not the one I knew so well.
You see, your individuality you felled,
The way instead of spontaneity
You radiate insincerity.
And in place of your old will to live,
And run and jump and follow our whims,
You now concern yourself with this shallow fib.
Now my patience with you's run thin.