I love the relationship dialog and the way it was designed, just that you have to kinda figure things out, but in a confusing way. I have been using Strapi for a long time now and it seems like this dialog still feels confusing though I understand what it is conveying.
The graphics just need a bit of nudging, nothing serious, just to make this whole thing a bit sensible:
If you look at the image above, the first thing someone sees is Comment allows you to select the field ‘answer’, and Answer allows you to select field ‘comments’. And the graphics in-between the 2 boxes are related to the fields only. The mind interprets this as follows:
So each time I see this and others as I come to notice is that, the graphic reads,
answer 
comments (sounds like comments has many answer 
)
and then just below it (which sounds correct, but confusing because of the first graphic above it):
which makes it confusing because the actual meaning is and the way this should be interpreted is:
I always think the graphics are wrong each time I see this, especially those 2 icons: 
Solution
The graphics just need a bit of nudging, nothing serious, just to make this whole thing a bit sensible like so:
This can easily be interpreted and decoupled from the actual fields and connects to the models instead. You don’t need to know any innereds to understand that solution. It’s dead simple to understand.
That line connecting the fields can be designed to show the connecting logic being done using arrow heads etc. «—• or •-----» or •—> or <—• or «—» or •—• or —> or —» or finally when polymorphic finally makes it to this dialog •—»? or •—>? etc