The right job for the right person:
A fool had eye pain. He went to the veterinarian and said, “Cure me.”
The veterinarian gave him medicine intended for animals and the fellow went blind.
The fool took the case up with a judge who dismissed the case: “If you weren’t an ass, you wouldn’t go to a veterinarian.
—Saʿdi’s Gulistan, translation by @sharghzadeh
After an age you don't feel sad because of heartbreaks or rejections, it will always be because of lack of money, constant career stress or not living upto potential.