If you aren't motivated to do it, then you have no motive.
If you have no motive, why are you doing it? (Oh, wait, that kinda answers itself...)
This is illogical. Nothing can happen without a reason. We should all be in a state of nonexistence, apathy, stasis...
There must be a reason... but what is the reason for the reason?
This requires an effect without cause, an underlying self-existent reason.
But, why? There is no answer. That is the answer. The answer is... ow, my brain...
I think too much.