As a lowly rated chappie - I will admit that I play harder against people ranked between 1,400 and 1,700 as those are the games where I may be able to spring a surprise. If those players aren't at least playing at 50% then they may be had!
1200 players are better. The chess rating system is structured so that the lower the number, the better the person it refers to, such as in golf, for example.
I have at least two games against people rated 1200-1500 where I took it too casually for the first 20 moves and now have to work in order to avoid a draw & loss respectively.