Final answer:
Groupthink occurs when the harmony within a group overrides the realistic analysis of opinions, leading to a consensus without critical evaluation.
Step-by-step explanation:
When a group's desire for harmony overrides its realistic analysis of other opinions, groupthink has occurred. Groupthink is a social dynamic wherein the desire for group consensus and cohesiveness leads to decisions that are not critically evaluated, with group members often self-censoring or altering their opinions to align with the perceived group consensus. This phenomenon can lead to suboptimal decisions and can be avoided by practices such as seeking diverse opinions, private voting, and withholding leader opinions until after group discussion.