Even for my "strictly RP" characters... I cannot resist clicking on topics, as many as possible, on NPCs... just so that the Topics section in my journal will fill up so I basically have an encyclopedia with me that I carry around and can refer to anytime just by hitting J.
I try to justify it sometimes with some characters... for example, he may be a very observant character and just "knows" a lot of Morrowind lore, or maybe he's the kind that likes to chat and interviews a lot of people, jotting the stuff down in his journal... but in reality, it's just my bad habit of clicking on a lot of blue text in the NPC dialog windows. ;(