The phrase "look daggers" is a term used to describe an intense, angry or threatening look. While there aren't any specific antonyms for this phrase, there are a few phrases that could be used in its place when describing a softer or more pleasant look.
Some antonyms that come to mind include "smiling warmly," "giving a friendly wave," "throwing a reassuring glance," "meeting with an understanding gaze," or "giving a supportive nod." These phrases are great alternatives to using "look daggers" and can be used in a variety of contexts, from friendly greetings to more serious discussions.