There is a portrayal of university that is common to many types of media. I didn't really expect these things, but I've seen many people who do.
"First year is easy" - well yes in comparison to the later years, but not in comparison to A level. I imagine most of the people who say this didn't get >85%. Even though a lot was repeated in first year (but taught properly), it was still much harder than A level. Don't be silly and aim for 40%, because when everything you did in first year is assumed knowledge for second year, you're going to have to do a years worth of catching up.
The notion that you will make the best friends ever and have lots of social time with them. Well, yes this does happen if you're used to it happening, going to university doesn't change you; if you've struggled with it before, you'll probably still continue to struggle with it, unless you decide to work on it and it's difficult to. Get used to being on your own for extended periods of time.
I've often seen people, say that you will sign up for every society club thingy in freshers week. But I've never signed up to a single one ever and I know people who are in the same boat.
"Student loans are free money" - Okay, so this one isn't common, but I have heard someone say this. No they are not, interest starts as soon as you get your first payment and it has to be paid back. OTOH, try to learn how student loan repayments work, because there is a false notion of it being crippling, when it's really 9% of income above a particular threshold that is paid monthly.
"Everyone is a left wing social justice snowflake" - If you think this you need to STOP watching YouTube and go outside.
And here are some of the things I thought, which were wrong. Many things I thought were very uncommon actually aren't; I thought no one believes in creationism in this day and age, well, nope there are some heavily devout people in religious societies. General knowledge too, I've met people who don't know what an HDMI or vga cable, what google chrome was and I thought that no one my age is that bad with tech at my age in this year. Nope some people are clueless with those things. And I thought the lack of knowledge of cooking and cleaning was just made up, surely everyone elses parents taught them how to cook meals, use a washing machine and how to maintain a house from an early age, right?? Well, people come in without knowledge of how to use basic kitchen appliances, which is sad.