What tablet apps are you missing?

So I often see articles talking about how the situation with android tablet apps is horrible. That there just aren't enough, and running phone apps isn't good enough.

I've certainly noticed a small amount of this, but I'm wondering what people are really missing. I was always bothered by the G+ interface until it was updated. I feel like the facebook app scales pretty well. Not a user of twitter so I don't really know its situation. However, Kindle, Play Books, Google Drive, Chrome, Talk, and few other apps really cover 90% of my usage.

Why I'm asking is that I'm wanting to venture into android development, and I would love some ideas of what people would find useful on a tablet that is just utterly lacking.