I always felt like the less-favored child and it still stings decades later. Does the Bible say anything about that?

“And when the LORD saw that Leah was hated, he opened her womb: but Rachel was barren. And Leah conceived, and bare a son, and she called his name Reuben: for she said, Surely the LORD hath looked upon my affliction; now therefore my husband will love me.”

Jacob loved Rachel and did not love Leah, and the text says so directly rather than smoothing it over. Then it says that the LORD saw Leah was unloved. When her first son is born she names him out of that word: God has looked on my affliction. In a book crowded with families who pick favorites, the narrator's sympathy goes consistently to the one who was passed over.

“And he answering said to his father, Lo, these many years do I serve thee, neither transgressed I at any time thy commandment: and yet thou never gavest me a kid, that I might make merry with my friends: But as soon as this thy son was come, which hath devoured thy living with harlots, thou hast killed for him the fatted calf. And he said unto him, Son, thou art ever with me, and all that I have is thine.”

The older brother in Jesus' parable stands outside the party with a grievance that is largely accurate. He did stay, he did serve, and nobody ever threw him a feast. Jesus does not correct his facts. The father comes outside to him, calls him son, and tells him that everything he has is already his. Being overlooked by a family is not the same thing as being overlooked by God.