Cavalry and chariots against infantry

[Domen]

they too were normally reluctant to charge enemy infantry

There are accounts of battles in which Polish-Lithuanian hussars were also reluctant to charge enemy infantry. The main reason was difficult terrain or infantry having field fortifications.

Also the enemy having lots of artillery (which can disrupt cavalry cohesion) was discouraging.

You guys overlook the fact that obstacles and field fortifications were used by infantry very frequently throughout history. Already Romans were using caltrops as far as I know.

Cavalry versus strong enough field fortifications built in difficult terrain is often helpless.

Strong field fortifications (such as wagon forts) was how the Hussites defeated undisciplined knights on numerous occasions - such a movie depiction of a battle from the Hussite Wars:

Field fortifications and obstacles (wagon forts, ditches, palisades, solid fences) can be seen:

http://www.youtube.com/watch?v=1qcFCWF5eLE