The supposed art of judging character from facial characteristics. We form first impressions from faces despite warnings not to do so. Moreover, there is considerable agreement in our impressions, which carry significant social outcomes. Appearance matters because some facial qualities are so useful in guiding adaptive behavior that even a trace of those qualities can create an impression.

Zebrowitz, Leslie A, and Joann M Montepare. “Social Psychological Face Perception: Why Appearance Matters.” Social and personality psychology compass vol. 2,3 (2008): 1497. doi:10.1111/j.1751-9004.2008.00109.x

Spanish currency was the peseta, divided into 100 céntimos. The "cuarto" was an obsolete coin dating back to the days when the main currency unit was the real (up to 1869); the real was divided into 34 maravedis, and the cuarto was not a quarter of a real but 4 maravedis, so there were 8-1/2 cuartos in a real. A real itself was equivalent to a quarter of a peseta. So a cuarto was a very small amount of money even when it was in use, which is the point here. The American Historical Review , Jul., 1898, Vol. 3, No. 4 (Jul., 1898), pp. 607-619

Two on his palms and two on his feet, where the nails that fixed Christ to the cross were traditionally believed to have been hammered home, and the fifth on his side, where the Bible says Jesus had received a spear thrust from a Roman centurion. https://www.smithsonianmag.com/history/the-mystery-of-the-five-wounds-361799/

In this strictly Christian times homosexuality is completely regarded as incomprehensible and isn't even suggested as an option for Sir Gawain.

"To complicate the consideration of those kisses: remember that if Gawain had succumbed fully to the lady's seduction and if he had honored the terms of his promise to the lord he would in fact have had to have sex with the lord-to yield his winnings, that is, his sexual conquest, in his own body, just as he has done with the kisses he received. Homosexual sex is thus one hypothetical fulfillment-in fact we might say the logical end of the interlocking plots the lady and Bertilak play out-but it is a forbidden end. Or rather, not forbidden, but unintelligible within the heterosexual world of this poem. It is in this way fully inside the culture of the poem (it is produced by the game the three are playing) however apparently outside it (unreasonable, impossible: Gawain and Bertilak?)"

Dinshaw, Carolyn. "A kiss is just a kiss: Heterosexuality and its consolations in Sir Gawain and the Green Knight." diacritics 24 (1994): 205-205.

People usually think action is a movement of the body of some kind and therefore inaction is just the absence of it, but inaction is an action. Sometimes choosing to do nothing is the best choice, but it is still a conscious action. https://www.wabashcenter.wabash.edu/syllabi/w/wattles/hkarma.htm

Philosophers in ancient times understood the correlation between a healthy body and a healthy mind. Even the most scholarly individuals were expected to maintain a workout regimen. The Bhagavad Gita is still referenced as a reminder for fitness maintenance. "Lord Krishna emphatically calls for maintenance of physical health though activity and exercise. He clearly states that one cannot even maintain his body without physical exercise. This is an apt reminder for people to remain physically active so as to prevent diabetes (the need of the hour), as well as for persons with diabetes/other lifestyle disorder patients to view exercise as an important part of disease management." Kalra, Bharti et al. “Coping with Illness: Insight from the Bhagavad Gita.” Indian journal of endocrinology and metabolism vol. 22,4 (2018): 560-564. doi:10.4103/ijem.IJEM_228_17 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6085948/