Why should you generally expect some error when estimating a parameter by a statistic?

When estimating a parameter using a statistic, some error is generally expected due to sampling variability; different samples can yield different statistics. Additionally, the statistic may not perfectly capture the true parameter due to biases or limitations in the data collection process. Furthermore, estimation methods often rely on assumptions that may not hold true in practice, contributing to potential inaccuracies. Thus, inherent uncertainties in both sampling and methodology lead to estimation errors.