Rainbunny, you should go to a Chicago Blackhawks home game if the anthem brings a tear to your eye 
. A truly for visiting teams. 'Jump Around' at U Wisconsin football games is amazing too.
Dragon, YABU to believe that Hallowe'en is American. Only the candy part is American. The rest is exactly as I remember it from my childhood in Dublin. It was always huge, a major holiday, one of the most important events in the calendar for children, and we spent weeks preparing for it.
Ditto proms -- they have been around in Ireland for decades, known as debutantes balls, or debs for short.
Teachers always got gifts in the primary school I went to in Dublin in the 60s/70s. By contrast, the elementary school my DCs attended in the US had a pto that organised a Christmas and end of year fundraising effort to get the teachers a cash gift each -- far better than 25 boxes of chocs or potted plants twice a year.
I love showers and gift registries, baseball, T ball, high school marching bands, school sports, separation of church and state, public education free to all and secular, public universities the most incredible aspect of the development of the United States imo is that state universities, engineering/mining and ag schools, and teacher training colleges were set up so soon after the settlement of the west. Also right turns on red, ease of learning to drive, driving lessons in high school, drive throughs, no front garden fences or walls, authentic regional barbeque and cuisine, TexMex and Mexican cuisine, 'The New York Times Cookbook', enthusiastic embrace of new things tea and curry have taken hold in many places since I first arrived, generosity of spirit - people are not constantly looking for the catch, and many details others have mentioned friendliness to babies and small children, especially if they have red hair the way that different generations relate well to each other... I would say Target but I grew up with Dunnes in Ireland. Third level education, yyy.
Dislike: Hersheys choc, Pledge of Allegiance (my DCs had been saying it for years before I realised it was part of their daily routine in school 
), the NRA, hyper patriotism, the way history is taught in elementary schools and even in high schools outside of AP classes, high fructose corm syrup, the bland taste of meats and veg and even fruit, the remnants of puritanism in domestic and foreign policy, the way people do not examine why their government is still trying to carry on the cold war, and the largely unquestioned assumption that it is fine to interfere in the domestic politics of other states, invade, topple governments, etc.