Disconnecting battery - Resetting driving habits

I had my battery disconnected and the radio memory was not affected but the mpg and mph stuff were all cleared!

does disconnecting the battery resets the ECU stored data?
i have read that the car learns how you drive and stores that information ... is that true and what else is stored there? I wonder if it is bad to disconnect the battery too often in modern cars!

 

forgot to mention that the car (accelerator) feels more responsive after the battery disconnect, like it is in tow-haul ... it could be my imagination since i was driving our slow car prior to this.

 

one of the mechanic told me that after a battery disconnect, the car may run "rough" for some time while it is reinitializing or recalibrating ...
I don't remember the last time I disconnected the battery and I have to disconnect it again and this time will try to be more observant. The mechanic was busy so I couldn't pin him down and ask more questions.