I am sure a lot of other applicants have the same problem.
What I did was:
1/1/1990 - 5/1/1990 - Country x - City y
5/1/1990 - 6/1/1990 - Country a - City b
and so on, as best as I could remember. In my opinion if I took a connecting flight, it doesn't count as a trip per say.
So if I entered Europe via France and took a connecting flight via same airport to Norway, I actually never visited France.
So I just wrote Norway in my form.
I have not submitted my application, so I might be wrong. bu this is my understanding of the situation.
You may also see it this way.
For example if you visited United States. You enter via Newyork and take a connecting flight to lets say, Chicago. Will you actually write Home Country to Newyork + Newyork to Chicago? No, you won't, right? You will write home country - Chicago. So its the same in this case. It were different cities in that case and different countries in this case.
The only thing I can think is when your previous stay in the connecting countries is long enough that some of your stays put you above the 6 months threshold. But I doubt that this is a very common occurrence.
I have a few China stamps in my passport, corresponding to transits. I just added a note saying that they are not actually trips but just transits to X Y or Z destination (Korea for my case where I used to work).