He doesn't understand why the hell all those Daleks survived while Time Lords didn't make it.
It's unfair, you know? Really, really unfair.
He's a Time Lord – a lord who conquers time – yet he can't control the time to ruin those pepper pot bodies into unimportant dust in the black hole with a planet with Satan in it. He has no power to destroy all the Daleks who trapped Rose in the other universe, tortured Martha, forced him to erase Donna's best times – oh god, oh god, how?
EXTERMINATE. EXTERMINATE.
If only he could destroy Daleks with Daleks' mantra along with Jammie Dodgers, maybe he can finally feel what peace is.