Despite speaking the same language, the culture is more different than one might expect. The shops are not open the extended hours we're used to, except for a few if you’re lucky enough to live near one of them. Terminology is different, some spellings are different and so are some pronunciations. Basic everyday life has subtle differences and the attitudes are also different.
Some things you will have to relearn, so it helps to think of it as an adventure. Imagine walking into a supermarket and not recognizing 90% of the brands. Recipes will be given in metrics, weighing your flour in grams instead of levelling cups. The controls on the appliances will look foreign, you'll need to relearn to use a washing machine, a dishwasher, the heating system.
See our forum Discussion of Pros and Cons, USA vs UK.