For fun, try it with a teleconverter 
haha oh you crack me up! 
what would you even photograph with a combo like that??
Well, I have one of those stories relating to my dad's cousin who was also a photographer (he did weddings and copies of the local College's parking passes

, but that's a whole other story).
Years ago he went to Florida with his girlfriend and brought along a 500mm mirror, a teleconverter and a tripod. While she was sunbathing (he's got the swiss cheese colored skin, so no sun for him), he was there on the beach snapping photos of busty babes in their bikinis. His girlfriend didn't mind as he always does juvenile things like that (even at well past 50). When he came back home, he had the rolls processed and pinned sets of photos on the billboard at work. In the same office, there was a girl who was a hardcore feminist... she looked at the pictures, gave him s*** saying he was disrespectful and all the kit that goes with it and went directly to the HR office to file a complaint. He thought it was just funny...
So, that's one thing to do with 1000mm... not that I recommend it nowadays. But the lens is small enough that people won't know you're photographing them close-up.