I have a whole LIST of them but I'll just share a few of my observations:

• There is a tic-tic sound (I think it's a hi-hat sample) in the second half of the choruses to Happy Ending (the Happy Ending, Happy Ending part). In the Japanese recording, the sample is panned to one side of your ear, but in the Korean mix from An Ode, it pans to the right and then to the left, possibly an edit when they wanted to remaster/remix the track for An Ode

• There was a doorbell that played during S.Coups' line (Call my friends, Imma celebrate) in Left & Right. The doorbell is rung because his friends are here

• Also from L&R, there is a new layer(s) of tracks that stack on top of the instrumental every time we enter a new chorus. In chorus 2, we hear the additions of a few brass stops, and in the final chorus there is a new layer of tambourine

• Woozi says "shyte, this is red too" in Ruby because he asked for a coke zero to avoid the red normal coke can, not realising coke zero is also red

• The bass line in the intro of Lucky is a reference to the intro riff of Thinking About U.

What else did you discover?