Trump was also very pissy at all of the EU but apparently Brussels in particular really hurt his ego

No what happened is that all of his backers want him to go after the EU because the EU is constantly suing American megacorps for breaking of local laws, and they don’t like that.

Trump is just doing their bidding, he isn’t actually angry at the EU, except because he has the vocabulary of a rather dim 8-year-old, everything is “nasty” and “evil” and “bad”.