turn someone's head

[I]t was plain that power had turned his head, and he would not be satisfied till all the power and all the wealth rested in his own hands. So he became swollen with pride, forgot it was I that had placed him there, and made preparations to destroy me.

Young men at Hillsborough—many of whom, I felt sure, had a smarter look than I—had bid stubbornly for her favour. I wondered, often, it did not turn her head—this tribute of rustic admiration.