Why did Robert burns think the mouse was luckier then he?

Robert Burns believed the mouse was luckier than he because, in his poem "To a Mouse," he reflects on the creature's ability to live in the moment without the burdens of human anxiety and regret. The mouse, having built its nest, faces the world without the weight of past mistakes or future worries, while humans are often plagued by their aspirations and failures. This comparison highlights the simplicity and innocence of the mouse's existence, which contrasts sharply with the complexities and sorrows of human life. Ultimately, Burns suggests that the mouse's carefree life, despite its vulnerability, embodies a kind of freedom that he envies.