When you're on the phone with someone and they keep talking to someone else they're with

Yes I understand I have the option to hang up the phone, and people are busy. But if you aren't going to talk to me, just tell me you have to get off the phone. I'm not going to be upset. I know people have other things to do. But sometimes people will just stay on the phone when they're with someone else and I'm just like ok I should have hung up 10 minutes ago if I knew it would last that long...