When to Use
- When you see your friends hanging out without you.
- Describing the feeling of being the third wheel.
- Reacting to someone else's relationship milestone while you are single.
Source: Batman: The Animated Series
Batman, dressed in his dark costume, hides in the rain on a rooftop while using binoculars to spy on a man and woman holding hands inside.
This is used as a reaction to describe someone observing a situation, secretly pining over someone, or watching something they wish they were part of.