It's particularly frustrating because I love the iPad. Like, it's one of the few devices I really, really, really enjoy in so many ways and I just wish it was better than it actually is. It's maybe the only device I own that I really do love. The Tab is a poor substitute and I really hate using it, but at least it fits with the rest of my tools in a sane way and gives me the freedom to customize it according to my needs.
Also, Notion. Another tool that I love the idea of, but hate the implementation. There are too many restrictions on the data model that make it frustratingly unlike any normal relational database and frustrating to use, and makes me wish somebody would just make a lightweight relational database with a friendly, practical wiki-like UI for building a knowledge base.