…what the subtext of the Beatles’ “Day Tripper” is. I assume there is one. What is the thing that took 'im so long to find out but he found out?
I’m gonna feel so wooshed in a little while, won’t I?
“SHE´S A BIG TEASER,
SHE TOOK ME HALF THE WAY THERE . . .”
Isn’t it kinda obvious? 
…ummm no … I see direction you’re going, but what does that have to do with the phrase “She was a day tripper”. Is this some British slang or metaphor?
Partial lyrics-
Day Tripper: I’ve heard this is a British slang term for someone taking a short, day-long (no over-night stay) vacation trip, usually by car or train. Fun for just the day. Hence the Sunday driver line.
I’m sure someone from the UK will come along soon with more information.
While your waiting, you might check this out (scroll down a little). It gives some other possabilities.
I could have sworn the line was “she’s a prick teaser, she took me half the way there…”
I’d have to say yeah, it’s pretty straight-forward. I didn’t think “Day Tripper” was exclusively British slang, at least since the song came out. The expression refers to someone who takes a vacation somewhere without staying overnight.
The song compares that to a woman who’s a cock-tease, who’ll get him started but not commit to going all the way (“she took me half the way there.”) To avoid any further confusion: by “going all the way” I mean “consenting to have vaginal intercourse.”
The second verse softens it up; it implies that he’s not talking about her going all the way sexually, but just that she’s getting him excited but will never commit to a romantic relationship. (“She only plays one-night stands.”)
(And astro, how are those “partial” lyrics? It looks like the whole song to me.)
I blame society.
In Astro’s defense, the line “DAY TRIPPER YEAH!” is repeated several times at the end, which Astro chose to omit. 
By the way, I wasn’t trying to be forum cop or anything. I really did wonder if there was a special version somewhere with a hidden verse that I was missing.
And it just occurred to me that the song messes up its metaphor. If she’s a “day tripper,” yeah, then she wouldn’t be a “one-way ticket,” but a “round-trip ticket,” yeah. A one-way ticket implies commitment.
Those guys were a bunch of hacks. I’m glad they broke up.
OK, thanks folks.
Yeah, I feel reasonably wooshed I guesss 
SolGrundy,
Not quite.
The bit about it being slang for someone who takes a day off for a quick vacation is spot on, but it is also a reference to someone who trips put on LSD or other drugs, which the Beatles were just getting into at the time the song was written.