How do lone pairs affect the shape of a molecule?

Lone pairs occupy space and create repulsion that alters the arrangement of bonding pairs, leading to a different molecular shape than if only bonding pairs were present. This can result in shapes like bent or trigonal pyramidal instead of linear or tetrahedral.

This answer is strong as it identifies the cause (lone pairs), explains the mechanism (space occupation and repulsion), states the effect (altered molecular shape), and describes the consequence (different shapes like bent or trigonal pyramidal). The question assesses the ability to connect lone pairs to molecular geometry.