An instrument is different becuase every song wasn't written to be sung accompanied. For example, the song I mentioned, "Lovely Agnes," sounds stiff when someone plays along. The only way I can think to describe it is "a loose 3/4 time." There are subtle pauses, etc., that get lost when it's played accompanied.
Sometimes, I just like to lead a song unaccompanied so that I can really appreciate the wonderful harmonies everyone adds.
...but I wasn't meaning to complain about you! I was referring to some actual events I'd experienced.
I know that, when I'm singing/playing, I'll either invite folks to join in before I begin, or folks will catch my eye as I go, and I'll nod if I'd like them to join.
Seriously, I've have many more pleasant experiences than bad ones--the bad ones just make better stories!
Denise:^)