The spontaneous reboot issue.
It has plagued several models of phones, for a year now. DX, TB and many others, will just reboot themselves, sometimes when you are not using the phone and it is just sitting there on the table.
Sometimes it happens several times a day, some times it goes a week or two without doing it.
I have seen it happening on too many phones at too many forums for it to be coincidence. There is a flaw in the OS, or in a very common app, and it needs to be addressed already.
I was hoping that the OTA would finally fix a problem that has been common since last summer, but apparently not.