Which known NPC dialog doesn't follow a logical "solution" or end?

Question

Inspired by this amazing answer I want to know if there are some other NPC dialog that simply until now seems "unfinished" or answer "incorrectly" leaving the topic unreasonably "open"

In the prior question we assumed that timothy was simply avoiding to answer us directly, but it was simply a bug in the dialog which lead me to question myself which other NPC ends a dialog abruptly without allowing us to progress into the conversation, personally I want to warn you that there are certain NPC that simply answer only specific things, even some of those get angry and cut the conversation directly so we must say hi again, so those could maybe work as intended, instead I'm trying to collect those who seems interested into the topic we are talking but suddenly and without a proper explanation or clue change the topic or stop answering.