There are too many to choose from. Here are some of my favourites:
'I want to belive'
'Woman! Get back in here and make me a sandwich!'
'How do I get it off my fingers quickly without betraying my cool exterior?'
'I think it’s remotely plausible that someone might think you’re hot.'
'But you saved me! As difficult and as frustrating as it's been sometimes, your goddamned strict rationalism and science have saved me a thousand times over! You've kept me honest... you've made me a whole person. I owe you everything, Scully, and you owe me nothing.'