...the left hand doesn't know what the right is doing. What do I mean by this? I mean that within the vast halls of Microsoft, you have teams working with blinders on. New technologies are cropping up all over the company, and apparently there is no one on the lookout saying: "Hey, that will break my software?", or "Hey, we're doing this, you want to take advantage of it?". One blatant example is MUI. Microsoft has totally rearchitected its MUI strategy for Windows Vista and is appartently evangelizing it to ISVs (although I haven't actually seen them doing it, not a single PDC session mentioned MUI). However, on the other side of the MS house, the Office team is apparently not making Office 12 MUI-capable. Yes, I know Office traditionally has its own MUIs, but neither Office nor the Office MUIs have any concept of the OS MUI.
Another example, actually the one that precipitated this post, is IE7 and MSDN subscriber downloads. Yesterday I gave in and downloaded IE7 beta 1 and the new security update. After installing both, I can no longer access MSND subscriber downloads; I get caught in a loop of singing in, clicking the subscriptions link, at which point I am automatically signed out at which point I have to repeat the whole process over again. The real kicker - Firefox doesn't have this problem. A MS competitor actually has better interoperability with a MS product than other MS products.