Will I ever understand?

I was getting ready to go to sleep yesterday night when in came an SMS from Lin. I do not quite remember the actual conversation but it went somewhat like this:

- Sleeping already?, she asked.
- Not really, was my reply.
- Watching some movie on the TV? Hehehe
- No, just getting ready to hit the sack. I am tired and have to wake up very early tomorrow.
- Ok. Good night.
- Ok. Good night.

I don’t know why but I had this impression she was pissed. Maybe it is her way of being kind and not preventing me from my well deserved sleep but is it normal in the region to interrupt the conversation so abruptdly?

In my country, a friend talking to me would have said: "Oh, ok. I do not mean to disturb. Just thought we could talk a little. We can talk tomorrow. Have a good rest." Doesn't it sound more polite? Or gentle?

If she was German I would have not thought much about it. Germans are usually very practical people. They make a phone call, the person answers identifying himself/herself by family name, the originator gives the message and hangs up. No need for 'how are yous' or ' goodbyes'.

Maybe it's the one quarter Dutch she's got in her blood... I will never understand.