I saw the changes from gaining freedom from Russian occupation and joining the EU with my own eyes.
We gained so much from EU, I don't know were to start.
Financially: we got a lot of our infrastructure built with EU funds (roads, etc.), if you see anything modernized even in the remote places of my country, you usually see a EU sign next to it.
Legally: there are always discussions about EU legislation, but a lot of it makes our lives better. Most recent example: smoked meat products will be allowed to be produced only with smoke, not chemicals.
Culturally: I used to be living in a land of grumpy cats interested only in themselves. To some extent it still is that way (see http://imgur.com/z5rYv). However the open borders policy has a big ongoing effect: most of the people have seen (or seen the effects on their friends) how people behave and communicate in the Western Europe. Majority of people have got more friendly, polite and positive about the future.