Operator precedence is so deeply burned into my brain I would never think of adding parens for it or modify the spacing.

I will use parens, however, for << and a couple other cases. It would be a shame to use lack of spacing to imply precedence, and yet get it wrong. Oops!

I also like to line up things to make vertical formatting of similar expressions, something a formatting program doesn't do. Hence I don't use formatters.