I go through moods. On one hand I like teaching people. On the other hand if I'm using the duty finder... I can't use this thing for networking as you're probably on some other server. I'll probably never run with you again so in the time I take to teach you something I'm only investing in that one run... no chance or re-playability.
Something like Caestrum we did 60 runs of (me (a SMN), a PLD and WHM pal of mine) and we had chat macros explaining every fight and every weird pull that happened in there. We didn't care if you watched the cut scenes... but we begged you to skip the two oddly placed ones at the very end with the ship raining down firery death and the two sword man cross cleaving your face. They don't add much to plot and SE really needs to create a better transition there.
At the end of the day there's no reason for me to be rude but there's equally no reason to be altruistic. Definitely a Catch 22.