The "Just Do It" approach to network design

The natural way networks are designed is "just do it". We just do
whatever seems obvious; very little thought is given to design.
Instead, neophytes think it's "just" a matter of configuration.

This approach leads to incomprehensibly complex designs. Cables going
in every which way, poorly-planned fault tolerance, VLAN
inconsistencies (e.g., VLAN 200 is one broadcast domain on this
switch, but a different broadcast domain on another switch), and
incredible difficulties when troubleshooting.