My wife bought me two commercial mice ("fancy mice") from the local pet store for my birthday in 2004.
As pets, mice have the following advantages: - They don't take up much room or eat much. - They are low-maintainance (no walks, no 3am barking). - They do have distinct personalities. - They are rather fun to watch or hold.
Mice move so quickly that when they're exploring a new area, their breaths are so fast the entire mouse vibrates! Their general movement and metabolic rate is incredibly fast.
However, the disadvantages are: - You can't take them for walks. - They will soil their cages, bedding, food, and water. - They have an attention span measured in seconds.
I don't believe that mice recognize humans as coherent entities: unlike a dog or cat, a mouse will not look into your eyes, and they do not appear to understand that different parts of you are interrelated. My suspicion is that they actually think of you as a place, not as a social being they can interact with.
Our favorite mouse is "Bob" (the black mouse), as he is friendly, explorative, and has excellent balance. Our other mouse "Wil" (the white mouse), short for "Kaiser Wilhelm" was so abusive toward Bob we had to put them in separate cages--male mice can be very confrontational. Except when Bob is in the cage, Wil is much more reserved and less friendly. It's possible that less aggressive, "underdog" animals make better pets in general.