I never really understood this until I studied TB Baba Kamma 87

A person who injures another person is liable for five different types of payment according to the Mishna. “One who injures another is liable to pay compensation for that injury due to five types of indemnity: He must pay for damage, for pain, for medical costs, for loss of livelihood, and for humiliation.” (daf TB Baba Kamma 83b, Sefaria.org translation) Daf TB Baba Kamma 87 continues the discussion about the payment for humiliation.

 “The Gemara presents another statement of Rabbi Yehuda. It is taught in another baraita that Rabbi Yehuda says: A blind person does not have, i.e., receive, compensation for humiliation, and so did Rabbi Yehuda exempt a blind person from all mitzvot that are stated in the Torah. Rav Sheisha, son of Rav Idi, said: What is the reasoning of Rabbi Yehuda? The verse states: “And this is the commandment, statutes, and laws” (Deuteronomy 6:1), to teach that anyone who is subject to civil laws is also subject to the commandments and statutes, and anyone who is not subject to civil laws, including a blind person, is also not subject to the commandments and statutes 

“Rav Yosef, who was blind, said: At first, I would say: If I hear one who says that the halakha is in accordance with the opinion of Rabbi Yehuda, who says: A blind person is exempt from the mitzvot, then I will host a festive day for the Sages. What is the reason? It is that I am not commanded and nevertheless I perform mitzvot.

“Rav Yosef continues. But now that I heard this statement of Rabbi Ḥanina, as Rabbi Ḥanina says: One who is commanded and performs a mitzva is greater than one who is not commanded and performs it, I say: If I hear one who says to me that the halakha is not in accordance with the opinion of Rabbi Yehuda, then I will host a festive day for the Sages. What is the reason? It is that as I am commanded, I have more reward.” (Sefaria.org translation)

“Tosafot ד"ה וְכֵן הָיָה רַבִּי יְהוּדָה פּוֹטְרוֹ מִכׇּל דִּינִים שֶׁבַּתּוֹרָה note that R’ Yehuda does agree that a blind person is Rabbinically obligated to fulfill all the commandments, lest he has no connection at all to Judaism. In Rashba’s opinion, however, R’ Yehuda exempts a blind person even Rabbinically from the Torah; rather, he performs mitzvot only out of piety.” (Note 8 page 87a1 in the Schottstein travel edition of Baba Kamma (3a))

I never understood why a person who is commanded receives a greater reward for the observance of a mitzvah that one who voluntarily observed the same commandment until I studied this daf with the Schottstein Gemara.

“One who is obligated to perform a mitzvah is more worried and anxious lest he not perform it than one who is not obligated, for the latter has nothing to lose, since he may simply ignore the mitzvah if he wishes. Also, since the obligated person performs the mitzvah despite such pressure and opposition from the yetzer hara (evil inclination), is more praiseworthy.

“Alternately, in obligated person by definition fulfills the kings decree upon him, where’s the non-obligated person is not. Thus the obligated person performs an inherently greater act.” (Note 11 page 87a1 in the Schottstein travel edition of Baba Kamma (3a))