[scorpius]

Thanks for the replies, knight46 and starsailor.
Yeah, normally, I would just play the chords while humming the tune when the adlib part comes and be contented with it. So, in that case no improvisation. Am I right to think that to improvise also needs some songwriting skills (which I don't have I think)? Because I might add something to a song that I am playing and yet I may not be satisfied with the result. Or something like that.