This thesis consists of three studies on economic behavior. The first two studies analyze the impact overconfidence on market outcomes and effort provision whereas the last one focuses on the impact of dishonesty on individual decision making. The first chapter uses a laboratory experiment to study the causal impact of self-confidence on bargaining with joint production. Self-confidence is exogenously manipulated by the means of an easy or a hard task. Relative performance in such task generates the joint surplus. The results of this chapter show that, when the joint surplus is low, overconfidence leads to bargaining failures, whereas most people settle on an equal split when the joint surplus is high. The second chapter analyses theoreti...