Ransom said:
So now that it's been established that yeah, we aren't just sitting around like idiots after the service waiting for something else to happen, is there a point to this?
Yes, and you apparently missed it.
Here, I'll help you avoid scrolling up.
"3 Let no one deceive you by any means; for that Day [of the Lord] will not come unless the falling away comes first, and the man of sin is revealed"...
Paul is assuming that, if the Day of the Lord came soon, his readers would be present to witness the falling away and the man of sin revealed first, otherwise this instruction would make no sense.
The final point is that this verse disproves the pre-trib rapture, since the man of sin is revealed 3.5 years after pre-tribbers say they will disappear. He's saying, "here are the signs you'd see first". But if they'd be poofed 3.5 years before the signs occur, there'd be no point in telling them said signs.
(Side note: I have my doubts about the whole "seven year tribulation period" thing, but my "proof" is going by what pre-tribbers believe, not what I believe.)