I have read through both fate and UBW and i find that his reaction is a bit wierd (understatement) when he is asked to have sex with Saber (fate route) and Rin (ubw route), his first expression is WTF?!one?, witch is fine since i think that most ppl would react that way, but instead of accpeting it i think he keeps this act up for a bit to long, but i guess it's abit unexpected the first time in the fate route. But he should get the small hints Saber sends him about her feelings for him and it's not like it's out of the blue when he has "sexual intercourse" with Rin, she did go out on a date with him, I mean that must say something to him about Rin's feelings. I mean he is a guy (i hope) and human, how can he not get the message?
So, am I the only one that thinks that Shirou is a bit wierd?