What is the most important physical difference between Lilliputians and Brobdingnagians

The major difference between the Lilliputians and Brobdingnagians is that of character. The Lilliputians though small in size were cruel, disrespectful and ungrateful towards Gulliver ... On the other hand, the Brobdingnagians though giant-like, were good-willed, virtuous and respectful towards Gulliver.