Yes, I have lasagna friends. I met most (all?) through my children, when they were at toddler groups, also in the school playground. In my experience, this is the number one place to meet people, and although not all my best friends have children the same age, I met them all either at my children's school or through friends or events connected to school.
I also met some people I'm not friends with...

I do also think that the therapy relationship can detract from friendships IRL. For me personally, therapy has often brought up issues that have made me by preoccupied, sometimes depressed or angry...it detaches me somewhat from my friends and children