Rabbi Yannai said: We are unable to understand either the well-being of the wicked or the tribulations fo the righteous. - Pirke Avos (Ethics of our Fathers) 4.15

Shmuel HaKatan said: When your enemy falls do not rejoice, and when he stumbles let your heart not be glad, lest G-d see and it will be displeasing... Pirke Avos (Ethics of our Fathers) 4.19

Sometimes, following the path is very challenging. :-)