I agree that animals and humans should not suffer. I just last november put our Copper (poodle) to sleep. He was 9 and we had him since he was 5 weeks old. We really miss him, but we feel that we did the right thing. He was very sick and we did not want him to suffer.
As for humans....well, that is a different story. I have been disabled now for over 6 years. I am in constant pain, yet do not wish to die right now. I think that people should have the right to make this decision for themselves.
If you want to be able to stop the suffering than you should have the right to make it stop yourself, but not ask someone else to help you.