Every Macbook I buy I use some sandpaper (medium coarse and then fine) to round the sharp corners between the sides and the surface containing the keyboard & trackpad. I especially round the sharp points on the corners of finger-cutout to open the lid.

I also slightly round the edges where the sides meet the top and bottom surface of the case.

The result is that those sharp unpleasant feeling corners are now silky smooth, around a 1 mm radii. I'm surprised Apple didn't design it this way in the first place.

Note: It's important to be cautious not get any aluminum dust in any of the ports or electronics.