2. "Allons-y!"
The Tenth Doctor has perhaps my favourite catchphrase: "Allons-y!" He explains to the uptight flight attendant in "Midnight" that it means "Let's go" in French. The expression is the perfect compliment to the Doctor: a bit quirky, a bit clever, and ready for adventure. Ten best employs "Allons-y" in his last episode before regenerating, "The End of Time." After a heartbreaking conversation with Wilf, which leaves both he and the Doctor vulnerable and without a solution to the insurmountable crisis, it seems as though the Doctor has lost hope. However, describing it as a word of consolation to the soul in times of need, the Doctor shouts "Allons-y!" one final time. It is the final push that both he and the audience need to know that Ten will not say his farewells until he has saved Earth one final time.