On this daf, we find that one rushes to eat chometz on Erev Pesach.
One man took particular pleasure in reciting Mizmor L’sodah. Every Erev Pesach, he was somewhat disturbed that he was not obligated to say his beloved kappitel. When he learned about the source, he was surprised to find that not all communities omit this tefillah on weekdays. The Rama rules that one should omit this on Erev Pesach since a thanksgiving offering wasn’t brought on that day. How could they bring this offering which was brought with chometz with Pesach the very next night? If they didn’t finish all the chometz, it would have to be burnt, even though one usually had until chatzos of that night to finish his korban todah, including the challos brought with it.
Despite this Rama, when the man checked the Sefardic custom, he found that the Kaf Hachaim rules that one should indeed say this tefillah on Erev Pesach. He wondered if it was permitted for him to actually rely on the Sefardic custom, since his attachment to the tefillah was so strong. When he asked a talmid chochom about this possibility, he wasn’t too surprised to find that it was indeed problematic.
“Although this custom is not according to all communities, as you pointed out, one who follows the Rama in general cannot say this tefillah when not obligated. The argument that it can’t hurt doesn’t apply here, since saying it when not obligated constitutes a hefsek, as the Siddur Bais Oved explicitly writes” (Shulchan Aruch, Rama; Kaf Hachaim 51:9; Siddur Bais Oved, Pesukei Dezimra, p. 66)