I like hills so I don't have any I really hate except one! It is a hill on our bike trail system in town. It really is not all that bad, short, but pretty steep. It is just right in the beginning of my commute to work, never warmed up, don't want to ride that hard that early in my ride to work, cold as h*$# in the winter, and don't really like to ride hard on a commute ride - so it is just a pain!