Newlines are important, but that's true of pretty much every language. Go does have more stringent requirements on where open braces are placed, but it's not a hard rule to remember (they always go on the same line as the code that opens the new scope). Also, this rule makes your code significantly less prone to breakage from errant edits and merges, since inserting a line can never separate your brace from the line it goes with. In this way, Go is actually more robust with respect to whitespace than almost any other language.

Note that in languages that don't mandate the open brace be on the same line as the code that opens the new scope, this can happen during a merge:

  // original code
  if (foo) 
  {
       printf("foo is true!")
  }

  // after the merge
  if (foo)
      someFunction()
  {
      printf("foo is true!")
  }

Now this code will always print "foo is true!". Because Go requires the open brace to be on the same line as the if, this type of bug is impossible in Go.

Gofmt will never change the behavior of your code, so you don't have to "worry" about what it will do. It only makes cosmetic changes to code, never functional.