Filming takes a lot out of you. It really does. It's immensely demanding, and you have to put the rest of your life in the icebox until you do your final shot. ↗
The first Superman film took up a huge chunk of our lives, but it was a wonderful time for us. We were young, my daughter was little, we were filming in London for a year, so we became like a close family. ↗
The camera does not like acting. The camera is only interested in filming behaviour. So you damn well learn your lines until you know them inside out, while standing on your head! ↗