help with the Nikon D50 manual mode

Hi All,

I was wondering about an issue with my D50. When in manual mode, it
does not always trigger... (it does 99% of the time though).
Isn't the whole point of the M mode to leave all settings to the user,
so we have complete control over everything?
Shouldn't the camera trigger work at all times and the picture be
taken, no matter how blurry/dark/... or unfocused it would come out?

My D50 works great in M mode in most situations, but then sometimes it
won't take the picture when not focused properly for example.
I know for a fact that this is not a problem with my specific camera
because I confirmed this on another D50.
Has anyone else ran into this? Did I misunderstand something about
this mode?

Thanks!

woorzel