One of the most inefficient practices I've seen done in companies is the company housing 50+ devs having to hire an expensive consultant who is only available on a limited time to figure out mysterious or in-depth problems with the company's main application (for example, JavaScript problems).

Then the whole dev team sits on his shoulders and production can't run smoothly until he fixes things. Even worse, him having the so-called qualifications, being the 'expert', but when asked an in-depth JavaScript question, they don't know the answer.
When I suggest to figure out things in-depth so problems like these can be prevented in the future, I'm met with: "Nah bro, we'll just apply quick fix #2" just because I carry the title 'Junior Developer'. Makes me want to hit my head on the wall on how stupid these people are.

This could all be solved if the dev team would be competent in the first place, knows how to read documentation and isn't lazy, most importantly. I hate teams like that.
Grab, the damn, documentation, read W3C, read MDN, get educated, and stop using band-aid solutions! Gah.
Toxic companies like these are what's wrong with some places in the development world.

I'm a proponent of knowledge.
Fellas, know your stuff.