There is a pause in mid-reach as the Doctor is clearly thinking of his answer before replying, "It seemed like a good idea at the time." He never predicted that becoming human would alter his perception of his identity so much. He could've never predicted it in the slightest, and he was so often teased by his own people, Do you wish to be one of them? Those monkeys? He was no better than they were.

The alcohol helped numb his anger, but only temporarily, and now he realized it wasn't the best decision he's made. Turning around and leaning against the tree, "I'll probably regret it later when the headache kicks in." Because he's human and that's what happens after consuming large amounts of alcohol, right? Even that will be a new experience for him.