I've been curious about this in my own practice, but I haven't yet been able to find an example of increasing suffering as having a positive impact on my insigh

I've been curious about this in my own practice, but I haven't yet been able to find an example of increasing suffering as having a positive impact on my insight. Do you remember the book or teaching that that analogy came from? Ajan Chah comes highly recommended from others as well. Edit: oh I guess the exception is clinging to the Dhamma, like the sutta about the raft.