Now, we all have things that we'd rather other people didn't know about. I don't necessarily mean deep, dark secrets – those sort of things are a matter for you and your conscience. I mean things like the list of gifts you are considering buying for a loved one's birthday. It would be a real shame if they saw the ideas list before the big day, wouldn't it?
To keep such notes away from prying eyes you might want to try an app like Note Crypt Safe with Password. The app name says it all, really. You can make simple text-based notes and then secrete them away behind a password. Notes can be tagged so they are easy to group and come back to, and they can be starred so you can easily identify the really important ones. Just don't forget your password, or the notes will be beyond your reach.
The free version of this app does enough, and the paid version adds in a few extra features such as search and automatic closing of the app after a period of non-usage.
Product: Note Crypt Safe with Password