A voice is very intimate. It's something of your own. So there's always this fear, because you feel naked. There's a fear of not reaching up to expectations. As you become more famous, people come and expect to hear something extraordinary, so you don't want to disappoint them. I feel this sense of responsibility.
I don't know if One Direction will stand the test of time. I have a niece who goes crazy for them. But the only way to judge art is to wait and see if it becomes evergreen. This takes a bit of time. Adele is a very good musician and I'd like to sing with her. But, again, time will tell if her music will become evergreen.