TL;DR:

• List Resizing : the backing array is grown by approximately 12% (in Java ArrayList grows by 50% when expanded2 and in Ruby, Array grows by 100%). The Python implementation optimizes for memory usage over speed. Another reason to preallocate Python lists when possible.
• Inserting at the beginning of a list takes linear time. Sometimes, better use Deques which trade constant time insert and remove from both ends in exchange for constant time indexing.

By Russel Cohen