What I don't find useful is when people just tell me what to do.
Instead of telling me not to go to Oxford, tell me about the things that surprised you at Oxford. I can make up my own mind about going, and the most effective thing you can do to help me decide is to tell me what it was like for you, without assuming it will be the same for me.
Now, if you tell me “Don’t visit restaurant $R in city $C, I got food poisoning and the service was awful” then I will probably avoid that place.
It should really be “If you go to Oxford for graduate studies, in department $D, under professor $P then you will probably have a bad time for the following reasons…”
> I would sit across from them in the dining hall, plates full of chicken tenders and french fries, and explain that postgraduate education in the UK is largely a way of extracting money from foreign students. Professors over there are checked out, classes are bad, and the whole place is pervaded with this sense of isolation and alienation, like everyone is behind a plate of glass.