I kind of experienced that but the relationships were more superficial than I'd have liked. If the "shared interest" is happy kids together it doesn't directly translate to the adults shared interests. But then again, maybe it was just me being me.
When we're young, we have nothing but time spent together. As adults, who spend an hour at the local park with some kids, those relationships require more effort to grow.
We have a few friends we've made through our kid, and it definitely takes more work to maintain - but it's been very worth it so far.
FTFY ;-)
It was so easy to make strong bonds as a kid, captive with other kids in a building most of the time. Now there is a cost:benefit I have to weigh a persons worth to me against.