Annoyance and surprise are inferred from tone.
While the use of the present progressive with the adverb "still" can deliver the required tone, it is not a guarantee that the tone of annoyance or surprise is present. Other queues are necessary to validate that annoyance (or surprise) was being expressed.
For example, I'm still typing. And I assure you I'm not annoyed, or even surprised by my typing.
Now some might read annoyance into my statement, but that's a problem of communication, which is how a message is received. I can give hints (as I did with my assurance) and improve how my message is received; but, absent these hints, the reader will receive the message according to their past experiences and beliefs.