Mentioning Girlfriend

I noticed that all of my German friends mentioned their girlfriend in our conversation at least once. Either when saying that they will have to go to their girlfriend this weekend, they remember her birthday and preparing gifts for her, or the girlfriend can bail him not to meet her for few weeks so he can work on a certain project with tight deadline.

Well, that's quite something for me.
I don't remember any Indonesian friend mentioning they have to do something special for their girlfriend. I mean, OK, I think of course all of them also meet their girlfriend at weekends. But, it never sounds to me like that is something obligatory to then, unlike when these people here said that.

So, I am asking, why?
Possible answers :
- from Indonesian culture itself, going steady isn't really
something "correct". So, mentioning your girlfriend isn't really popularly done as mentioning your wife.
- German people considers their girlfriend more special than Indonesian people consider theirs, so they really have allocated time and obligations for her. (Hmm, if this is the correct answer I guess I'll have to hunt a German boy here ;) )
- German people are really busy with everything, so they even have special time and effort allocation for their girlfriend. Just as all of their works.
- In our age (I'm 22, but my friends are mostly older than me)it is just natural that everyone should already has a girlfriend. So, it is just natural to talk about it, it's a part of everyone's life.
- (or in contrary with above reason..) Not everyone has a girlfriend. Mentioning her will raise your self esteem and tell to others, "hey, I'm in relationship".
- They just use her as an excuse =)


No hard feeling =) anybody has better idea?