What are polar patterns?
A polar pattern (or pickup pattern) is the area a mic listens to. Cardioid is for one person, omni is for a group, shotgun is laser-focused.
Think of your mic as a torch. The area it shines a light on is the area it's 'hearing' your voice.
Most mics you'll come across — including the Samson Q2U — have a cardioid polar pattern. Cardioid is heart-shaped and designed to record one person at a time.
Other common patterns
Omnidirectional: a full circle, for recording multiple people around the mic. Bi-directional (or stereo): figure-of-eight, for two people facing each other. Shotgun: a laser-focused pickup that blocks out everything around it — think of a news reporter on a busy street whose voice you can still hear clear as day.