Rosh Hashana 16b - Confusing the Satan

The gemara says that we blow shofar both sitting (prior to shemoneh esrei) and standing כדי לערבב השטן, in order to confuse the Satan. Tosafos cites the Aruch to explain that the Satan upon hearing the second set of tekios will think that Moshiach is coming and he will be killed, so he will be too distraught or distracted to prosecute agains klal yisroel. Rashi and Rabbeinu Chananel take a much simpler approach. They say that the confusion to the Satan will be caused by the repeating the mitzvah which will demonstrate love and endearment for the mitzvah. The Satan will be automatically silenced by our demonstration of love for mitzvos. The Ran has a third approach that the sound of the shofar humbles the yetzer horah. It seems from the Ran that the Satan is not referring to an external angel who speak bad to Hashem about klal yisroel, rather it is referring to the Satan/Yetzer Horah within each person. The shofar will remind the person to submit himself before Hashem, and not yield to the infulence of the yetzer horah.
I would like to focus on the approach of Rashi and Rabbeinu Chananel and its connection to Shavuos. The gemara says in Pesachim 58b that although there is a dispute whether לכם, personal enjoyment is necessary on most yom tovim, all agree that on Shavuos it is necessary - יום שנתנה בו תורה הוא, it is the day the Torah was given. Rashi explains שישמח בו במאכל ומשתה להראות שנוח ומקובל יום זה לישראל שנתנה תורה בו - to rejoice with good food and drink to show that this day is pleasant and accepted by yisroel, that the Torah was given on it. In other words, the avodas ha'yom of shavuos is to indulge and partake of a feast to show the importance of the day. I saw in the sefer Ohr HaChama on the M.B. (from Rav Zundel Kroizer zt"l who just passed away) an interesting question. Why would physical indulgence be the avodas hayom of Shavuos? Wouldn't it make more sense if the way she demonstrate appreciation for the Torah is by learning Torah (which we do)? Why would the halacha dictate otherwise? He explains that on Shavuos klal yisroel accepted the Torah, but the gemara says that they needed to be coerced into receiving the Torah - מלמד שכפה עליהם את ההר כגיגית. Learning Torah would demonstrate that we feel connected to the Torah but it would not necessarily indicate that we are happy about it. Chazal instituted that we physically indulge as an expression of happiness and excitement, to demonstrate that we are happy to have received the Torah and it isn't something that was forced on us against our will.

In general, the קטרוג that the Satan will have against klal yisroel is not that they don't perform mitzvos. We do perform mitzvos. The issue is that we often lack the excitement and enthusiasm in the performance of the mitzvah. We do it in a way that makes it seem like a burden. Therefore, the way we counter this kitrug is by blowing twice, to show that we want to be connected to the mitzvah as much as we can and don't want to let go. That is what Rashi means - שלא ישטין כשישמע ישראל מחבבין את המצות.