Hi, wowenglish1. I like your question because I'm often puzzled by the same question.
I'd like to copy some sentences taken from Oxford and hope our great teachers here can help us:
Even if we could go, which is highly doubtful, John wouldn't be able to come with us.
If you're all going to the party, you can count me in, ie I will come with you.
I don't want to come with you today.
We're going to the cinema tonight. Do you want to come with us?