What you do when you dont want to pickup a call on your mobile phone?

If calling number is from Bank collection agencies, then I dont tend to pickup the call. But if it is from a colleague from your workplace and if I am watching an important show or in emergency work, then I switch off or keep pressing Busy button on my mobile. Sometimes, I will be in a fix if my boss calls as he doesnt like people not picking up when the situation demands. Even I got blasting for this also once. So when my boss calls, then I promptly pickup the call and tell him that I am in another location. If my family member calls and if I am doing an important task, then SMS will do the job.

I have seen most of the people either giving to their friends that to tell the caller that he is not available or doing other tricks. Whats your take, mylotters?