The next chunk of the Mishnah in Megillah contains a long series of statements connected not by content but by structure. Inspired by the mishnah on 6b that said "There is no difference between Adar I and Adar II except the reading of the megillah and matanot la'evyonim [gifts to the poor]", we go on and riff on the theme of "Ein bein X v'Y ela Z" / "There is no difference between X and Y except Z." We got to 5 of these 10 little vignettes. For each of these, the Gemara assumes that Z is very well-specified, to mark a very sharp line for exactly where the similarities between X and Y end, so anything not specified in Z is assumed to be the same for X and Y.
1) Topical during this holiday season: There is no difference between [the prohibitions of work on] Shabbat and Yom Tov except ochel nefesh - the food for each person discussed in Exodus 12:16. You and I might read this to mean that building or plowing is prohibited on both Shabbat and Yom Tov, while any work related to food (to be eaten that day) is prohibited only on Shabbat. And Rabbi Yehuda would agree with you. But the opinion that the Gemara imputes to the Mishnah says that it's only ochel nefesh itself that is permitted on Yom Tov, and machshirei ochel nefesh (this might refer to peripheral work that is indirectly related to food, or might refer to tools that are used for food -- Rashi gives the example of sharpening a knife that got dull on Yom Tov) is prohibited on both. The resolution is that if it was possible to get it done before Yom Tov, then it should be done before (and not on Yom Tov), and if it wasn't possible before, then it can be done on Yom Tov.
2) Even more topical for this week: There is no difference between [the prohibitions of work on] Shabbat and Yom Kippur except that the punishment for Shabbat is by human hands (stoning!), and the punishment for Yom Kippur is by divine hands (the mysterious kareit). Therefore, Shabbat and Yom Kippur are equal in regard to payment: If you go on a destructive rampage on Shabbat and cause $100,000 of damage, then you would be liable for $100,000 (for the damage) and your life (for violating Shabbat). Except that you're already paying with your life, so you don't have to pay the $100,000. And the same is true for Yom Kippur, even though no human court can sentence you to death. So I suppose the lesson is that if you want to go on a destructive rampage, do it on Yom Kippur (if you're not afraid of kareit). We get some discussion of whether multiple punishments (humanly applied and divinely applied) can be applied for the same offense, e.g. kareit and makkot (lashes) - not everyone agrees.
3) Sort of topical this week, since we'll annul vows at Kol Nidrei: There is no difference between one who vows to get no benefit from someone, and one who vows to get no food from someone, except passing through on foot, and implements that aren't used for food. Thus, implements used for food are included under the "no food" vow. But what's with the passing through on foot? People usually don't care about who happens to walk through their hard. Ah, but when a vow is made, people start caring about things they wouldn't normally care about.
4) More vows: The difference between a neder and a nedavah. A neder is when I say "An olah is hereby [incumbent] on me." A nedavah is when I say "This is hereby an olah." The difference is that if the animal intended as a neder dies or runs away, I still owe one olah from somewhere, whereas if the nedavah dies or runs away, I don't owe anything. However, they are both subject to bal te'acheir (which we read all about back in Masechet Rosh Hashanah) - the idea that the vows have a due date after one festival, or three festivals, or the conclusion of this festival cycle (go to Rosh Hashanah to read all about the dispute).
5) There is no difference between a zav who has seen two sightings and one who has seen three sightings, except that the latter has to bring a sacrifice (see Leviticus 15:14). But otherwise, they're equally tamei, and have to wait 7 days before they can dunk and be tahor. This is based on a typically close reading of Leviticus 15 that I don't really have much to say about. Hint: count the instances of the root "zav", and you'll reach the same conclusion.