Use this when you're in an awkward social situation and feel uncomfortable about where to direct your gaze. During the surprise party, when he didn't show up, I didn't know where to look.
Pro Tip 2/3
Avoiding Tension
It expresses the desire to avoid eye contact in tense or conflicting situations. When they started to criticize each other, I didn't know where to look.
Pro Tip 3/3
Witness Discomfort
Used when you witness something that makes you feel secondhand embarrassment. He spilled coffee all over his shirt during the speech, and I didn't know where to look.