Fragmentation

...One of the main reasons why UIs are unequally inferior are not only the way you build apps (open vs. closed hw/sw system) and the SDK itself but also marginal to non-existing UI standards, no ready-made drag & drop UI items, variations in carrier- & device firmware, hard- & software input, screen sizes, international customizations, modded phones, rooted phones and last but not least completely different expectations among users and the linux’ish target group itself. in a nutshell: beautiful mess. obviously, all these reasons eat up a huge pile of time that one could better spend with improving UX and polishing the interface. those who started early with android development have learned and are still learning it the hard way, just like they did with win 3.1 back in the days.