Obstacle
An obstacle on your path acting like a barrier indicates that you are blocking your progress with regard to the subject matter of the dream. This is regardless of the fact that you did not put the obstacle there in the dream. If you know who put it there then you are letting the influence of that person block you from doing what you need to do. If it is non-personal, such as wet cement on the pavement, you need to improve the health of your colon in order to continue in the direction of your goal.