"Notes" section where you could write your own notes to read later?
The lack of this feature in most RPGs and open-world games didn't use to bother me, but about 2 years ago I played the first Deus Ex (yes, heresy to play it that late, but, in my defense, I played the horrible Invisible War a year after that to pay for my sins!), and after noticing that I could create my own in-game notes in my journal, either editing the ones game gave me or making new ones, I was using it CONSTANTLY, either to write down computer passwords that I read or clues that other NPCs gave me. It sped my progress along by eliminating backtracking, increased my immersion because I could make my own decisions on what information is important as JC Denton. I'd come to a lot of situations where minor information was useful 0.5-1 hour after I gained it, thanks to the rather large levels.
As an example, in Morrowind (I believe it lacked this feature, though I could be blind), a few times an NPC would give me information (i.e., an unmarked quest) and the game would word it entirely differently in the journal, sometimes leaving out vital details that I'd only be able to find again after going through about a 100 "little secret"-titled subject quotes. Anyone who's played Morrowind will know that you sometimes leave a quest hanging for maybe 20 gameplay hours until you're in a position where you can complete it without too much hassle.
Now of course, there is always the option of writing it down on paper or a Notepad file, obviously. However, I play most PC games in full-screen and sometimes it's easy to lose physical notes. By having a Notes section in your journal, you can tie a bit of information to your save file itself. Heck, developers put tutorials and manuals into the game itself even when you commonly get a proper paper or .pdf manual regardless, right?
Anyone else here who'd like more games to add this feature?