Hi, Can any girls here tell me, do you understand what your bf's thinking always?

example :

(1)IS your bf looks moody, but he never want to tell you what happen to him? 

(2) Always when come back from work, he did no much thing to talk with you, but when outside mamak, he did got a lot of thing to talks with friends?

Why always i cant get understand what's men thinking ? If being a couples, we need to share thing to each others,correct?

Girls is always worry,care,concern and love to tell everything if she is facing some funny ,sad,happy happens, but why guys wont? Is they really so good and everything is keep in mind and dont want girls(gf) to worry about??

so many questions am i, because i am confusing.