The Ben Ish Hai (Rabbi Yosef Haim of Baghdad, 1833-1909), in Parashat Nisavim, addresses the question of which foods should be eaten and avoided on Rosh Hashanah (listen to audio recording for precise citation). He writes that one should not eat sour foods or foods cooked with sour ingredients on Rosh Hashanah. Similarly, one should avoid fruits that have yet to ripen and thus have a bitter taste. On Rosh Hashanah we should conduct ourselves in a manner expressing our hopes for a sweet, pleasant year, and we should therefore avoid sour or foul-tasting foods.
By the same token, the Ben Ish Hai writes, one should partake of tasty meat and sweet foods and drinks on Rosh Hashanah, as an omen for a good year. He cites in this context the verse in the Book of Nehemya (8:10), which tells that Ezra and Nehemya instructed the people on Rosh Hashanah to eat "Mashmanim" (filling delicacies) and to drink "Mamtakim" (sweet drinks). Eating and drinking on Rosh Hashanah serves as an auspicious omen for the coming year, and also expresses our confidence in a favorable judgment.
The Ben Ish Hai adds, however, that one should not overindulge, but rather partake of good foods and drinks in moderation.
It is also especially important to avoid anger on Rosh Hashanah. Anger is, of course, destructive all year round, but, as the Ben Ish Hai writes, one must exercise particular care to avoid anger on Rosh Hashanah because anger on this holiday is an inauspicious sign for the coming year.
The Ben Ish Hai also rules that women should make every effort to have the table set and prepared before their husbands return home from the synagogue on the night of Rosh Hashanah, as this, too, serves as a good omen for the coming year. He emphasizes, however, that if the husband comes home and sees that the table is not prepared, he must not grow angry. He should instead accept the situation as it is, and not express anger or even feel any resentment at all in his heart. Avoiding feelings of anger is an especially important part of our effort to ensure a good "Siman" (omen) on Rosh Hashanah, and one should therefore eliminate all feelings of anger as much as possible on this day.
Summary: It is proper on Rosh Hashanah to partake of sweet, tasty foods and drinks in moderation on Rosh Hashanah, and avoid foods that are bitter, sour or otherwise foul-tasting. One must be especially careful not to express or even feel anger on Rosh Hashanah. Women should try to have the table set before the men return from the synagogue on Rosh Hashanah evening, but a husband must not be angry with his wife if the table is not set when he returns home.
