We all know that 18 is based on averages and that until recently the threshold for some rights was 21. Kids at 18 don't seem as mature as they were a few generations ago, with their ability to reason crippled by desperately short attention spans. We didn't have computer games or channel-surfing in the 1960s. For example I would say that anyone who starts smoking has shown an indisputable inability to run his own life. I don't care how old he is.