I think Brazilians have a hard time understanding European Portuguese mostly due to the closed vowels and how fast we speak. There are also some words that are different like banheiro instead of casa de banho, or Γ΄nibus instead of autocarro , or even suco instead of sumo, but I think mostly everyone will understand what you mean, especially in more urban areas like Lisbon and its surrounding area. I reckon Porto and Braga too.
Although I had a hard time understanding what the hell meia meant when you mention it in the middle of giving out your phone number or that jogo da velha is the Brazilian Portuguese equivalent to cardinal or hashtag.
Anyway, I like to think it's a softer version of an American going to the UK. You'll probably going to do just fine in more urban areas, and will have a bit more trouble in rural areas. I'm guessing you're visiting the country. If so, I don't think it warrants studying European Portuguese.
As for the attitude, yes we can be condescending towards Brazilians, unfortunately. I'm Portuguese so take this with a grain of salt, but it tends to happen more with people from around 40 years old and up and less with younger people, in my experience.