I'm sure it has to work that way with business calls. The only people that call me is family, and they usually call when they know I'm not at work. I don't even answer calls if I don't recognize the number. I don't answer school calls or e-mails on weekends, because I don't want them to think I'm at their service anytime and anyplace.It's not that I have to say that... I do it as a courtesy.
No one likes to be on their phone that much but for some people it's a necessary evil. People know when your being honest and sincere. It goes a long way in developing or maintaining relationships. If your honest they understand if they are worth fooling with.
It's just the "I got busy" is a red flag because it usually goes along with you having to track them down and an attitude that they didnt want to talk or do it.
Like Fence is saying. At one point I sat down every morning and evening with a yellow pad and returned calls, and texts to people. Some time it didnt worked out and got pushed to the next day. Even if I handed them off to some one else I text them and told them so and so would be contacting them.
I usually average two calls a day. I visit some people, and their phone rings every 5 or 10 minutes.