salam ..
well ... the beard thingy .. whenever i ask why is it obligatory they say to be different than the kafirs.. and because the prophet pbuh said in one of his hadiths (heffo ashareba wa atleko alleha) .. but the hadith is like very vague and u can't tell why he (saw) said it or in what occasion. also the story when a sahabi (can't recall his name) asked the prophet give me a reason so i can kill this kafir ... and the prophet allowed him to kill him :S:S don't remember the story well .. but it made me doubt the authenticity of the hadith .. because if you want to write a hadith like this about our beloved prophet (saw) you should be careful and say why he did this ... IFF he really did it (allowed the sahabi to kill the kafir guy) ...