(I apologize in advance for how OT this is...but I can't help myself.)
So Big Bang wasn't the first place that theory was postulated. (
That Indiana Jones in the end has no effect on events.) It was just sort of popularized from that. But in fact BBT's Amy is completely incorrect in summarizing the movie - but I won't get into that here. However, you can read one rebuttal here:
http://www.indiewire.com/2015/02/indiana-jones-and-the-misunderstood-character-arc-133065/
I also think the 2nd movie is GREAT. It lags quite a bit in the middle, but it's a rip roaring adventure film for 3/4 of it's run time. (It's also the film I have seen the most times in the theater - seeing it 11 times in the summer of 1984) The third movie I loved at the time it came out, but watching it today it's to me the weakest of the 3, too much jokey joke, and too much repeating of the first movie, but still a solid yarn. I haven't seen Crystal Skull since the theaters even though I own (inherited) a copy on DVD, but I am sort of afraid to watch it.