I don't get very good cellular reception in my office and so I tend to miss phone calls. All I get is a notification that I have a voicemail. That can be terrible when you're waiting on a doctor's call or any number of other situations. I also don't enjoy talking on my cell phone when I'm at home and would prefer to talk on a normal landline phone.
I wish my cellphone could realize where I'm at and then forward all my calls to a certain number. Currently, call forwarding is an all or nothing premise. You can turn it on inside the Settings app but only select one phone number. I'd love to be able to set up locations, such as "work" or "home" and then select specific numbers for those locations to forward my calls.