A common error individuals make when starting a fitness program is setting unrealistic goals. Many beginners may aim for rapid weight loss or an extreme fitness change without considering their current physical condition or experience. This unrealistic expectation can lead to frustration, disappointment, and potential injury. Instead, it's important to set SMART goals (Specific, Measurable, Achievable, Relevant, Time-bound) that are both challenging and attainable. Gradual progress allows for a sustainable approach to fitness, helping individuals build confidence and maintain motivation as they see consistent results over time.