Ideally, we should all be developing our code in our own little space on our own little local server. This allows us to easily make changes without messing up production code or stepping over other's work. This is usually cost prohibitive so we're "forced" to use virtual machines to make this a reality.

The problem we face is that each developer needs to have a virtual machine that is setup exactly (or nearly exactly) like our production server. This requires a long list of configuration changes that need to be made on every machine. For example, install the apache package, update this configuration file, setup MySQL so you can access the databases remotely. Then we run into more problems when additional changes are needed because the developer has to take time out of their schedule to make them on each machine. There are also passwords that have to be remembered and /etc/host changes that need to be made. You'll be in even worse shape if the deployment consists of multiple VMs.