Choice.

I'm starting to enjoy Economics, in an odd sense.

But yes, main problem is always about choice.

I think I choose not to like you anymore.
Don't know why.
The feeling has shifted so quickly, in such a short period of time.

It's good, perhaps.
I really need to concentrate on other matters.

As for all the frustrations I've been facing, I'll try to resolve them whenever I can.

Seriously, which of us should apologise?