The million dollar question. There are so many stereotypes hovering around this question since it is "difficult" because Europeans are reserved and cold or even "impossible" because they do not like to interact with foreigners.
From that first moment when you arrive in a foreign country, with so many stereotypes in mind, it is the only thing you find because it is the only thing you see.
And no, it's not like that. Everything is based on how you open up, how you try to get to know their customs and their lifestyle while wanting to be part of it (because you are now in their country to discover and try new things!). When I got to Prague, I thought it would be very difficult to find friends, that I would be alone because I don't speak Czech very well or that they would not be interested in meeting me. I arrived with good and bad stereotypes that initially limited me a lot.
When I started going to language exchanges, with my mind free of 
what I thought I was going to find, when I was willing to experience new things and see beyond what I am used to, everything changed. I was quite surprised to have met my best friend. He is a Czech who speaks Spanish! And what a surprise, since we met, I opened my heart and I was willing to meet him and offer a sincere friendship ... and that's how it happened! I have enjoyed the best moments in Prague with him because although there are so many stereotypes around Czechs (and around everyone), they are nonsense.
And I have not only met my best friend Jan but a large community of Czechs and expats willing to break that language barrier (in my case, Spanish) and offer me that warmth that made me feel at home. I think it also depends a lot on your mindset towards situations and towards people. It's something that if you 
think it's going to happen, you'll attract it. If you want a different result, start thinking differently, start to eliminate those stereotypes and know the scene of the person. In a language exchange that I usually go to, I met a Russian girl who speaks 11 languages! She surprised me so much, even more, given her age (16 years old). We started talking (in Spanish) and we became very good friends from the first moment. In each meeting, I meet a different person who surprises me and makes me admire the world around us, makes me want to know more about the soul of Prague.
I have met people from all over the world who are so interesting that I think one day in Prague it was enough to think something: it was the best choice I could have made.
And the soul of Prague is its people.