Sideways logs and quartz pillars have improperly rotated/flipped textures. These issues are not really noticeable with vanilla textures but they become apparent if you are using a texture pack with any sort of shading. I propose these changes to their rendering:
North-south facing log/pillar:
1. West face flipped horizontally
2. East face rotated 180 degrees
East-west facing log/pillar:
1. North face rotated 180 degrees
2. South face flipped horizontally
3. Bottom face flipped north to south
4. Top face flipped east to west
This way the direction of shading becomes consistent with other blocks.
This is not the same issue as
MC-1451 as I think that particular issue is unfixable short of adding a separate horizontal log texture for each log.