Tropes that make no sense - the 'I Love You' pickup line

I was watching the first episode from the new season of House the other day, and found myself irritated that they decided to repeat one of Hollywood's most nonsensical staples: characters who declare that they love someone, either immediately after the first kiss, or (even worse) before they've even kissed for the first time.

Honestly, is there anyone who is a) above the age of 13, and b) not a functional retard who has actually done this? Is there anyone, man or woman, who would not frantically start looking for the exits if presented with this pearler of a pickup line?

I suspect part of the reason for this is that scriptwriters need a quick way to create emotional tension. Just putting a margin note to the effect of 'have a bunch of slightly awkward pauses and uninspired sounding conversation as you both look a little too long at each other, then look away pretending it didn't happen' might be a bit hit-and-miss for some actors. But Hugh Laurie? Really?

In the episode, Cuddy remarks that 'I told you I loved you, and you didn't say it back.' House has some throwaway joke to brush it off, which sounded jarring given his character. Surely someone with such a piercing (albeit cynical) understanding of human nature, along with a healthy dose of misogyny, wouldn't just let that slide?

My answer would have been 'No $#!7, eh? That's because we hooked up for the first time less than 24 hours ago, and that's not quite how love works for me.'