Writing on different gadgets

I don't currently have internet at home. I have it at work, and I have my iphone. One of the more odd things this has taught me is that my writing is significantly worse on an iphone. I don't really understand this, if anything having to slow down while I write seems like it should improve my writing. But whenever I am on a computer and edit anything I wrote on an iphone I am really shocked by the silly errors I make.