When it comes to config files for any kind of application, I tend to make sure that I understand what each config does, and that for each environment, they have the correct settings.

However some of my co-workers don't bother understanding what the configs mean and so I have people copying and pasting config details from development environments into staging and production configs. They think that just changing hostnames is more than enough.

So they ended up wasting a good 3 hours trying to figure out why sessions were always invalidating and cached objects were not caching. I had a look at the config and realised their mistake in like 3 mins.