Dave,
I've got an Alexander Scale Model (ASM) Pennsy Flagstop that I'm putting together for a friend of mine. (Sorry I don't have a convenient picture of it to post.) These old wood kits were originally die cut and the roof lines don't always line up when you lay the card stock roof on top, which leaves gaps. The roof is also in four separate pieces (like a dutch hat) so aligning these has been challenging to think through.
I also have a Walthers Miss Bettie's Diner that needs some more detailing and kitbashing:

When all the seating is added to the diner that comes with the kit - particular the booths - there isn't enough room leg room for the patronage. I need to remove a couple of the booths in order to make it realistic. This will require some re-alignment of the furniture to figure out which arrangement will work out best. Hardly frustrating but will require thinking it through.
Lastly, I have some interior lighting projects that I have a few options with. I just need to make a decision on each one of them then carry it out.
Tom