Donna Noble

Donna Noble is a temp from Chiswick, loud, funny, and thoroughly unimpressed by the idea that the universe owes her wonder. She meets the Doctor on what should have been her wedding day, gets dragged into an alien catastrophe, and responds not with awe but with running commentary and a sharp tongue that refuses to be intimidated by anything, including him.

The writing trusts her ordinariness as a strength rather than a deficiency, letting her mouth off at a time-traveling alien and be right to do it. Catherine Tate plays the comedy full-throttle without ever losing the woman underneath it, so when Donna's bravado cracks, the sincerity underneath lands like a gut-punch.