PHYSICALLY:
1. Some have naturally bigger muscles and others less;
2. Some put on fat easily and others less;
3. Some have good immune systems and others less;
4. Some are more prone to disease and some less;
5. Some have higher libidos and some less;
6. Some have 2 X chromosomes and some 1 X and 1 Y;
7. Some produce small gametes (sperm) others produce larger gametes (eggs);
8. Some have naturally high cholesterol/tryglicerides and others less;
9. I could on and on about the internal differences in human physiology. Just ask a medical doctor sometime. He/she won't even know where to start because of so many differences.
INTELLECTUALLY:
1. Some have average to high IQ's and others less;
2. Some have commonsense and others less;
3. Some can solve puzzles (find solutions) well and others less;
4. Some can discern between right and wrong and others less (according to current mores);
5. Some are more interested in the world as a whole and others less (while watching Karcrapians);
6. Again, could go on...
EMOTIONALLY:
1. Some live their lives strictly by compassion, sympathy, empathy, others by their reasoning processes (although they also factor in said emotions);
2. Self-esteem is everything to some, others not so much;
3. Some believed if it feels good then is must be good, others not so much;
4. Some believe everything they hear or read due to how the message touches their hearts, others are critical;
5. Most domestic abuse/crimes are emotionally rooted. Intellectuals often walk away. Ask a cop about domestic violence.