Sometime last year I had an internship at a small company.

Test servers weren't a thing, and after local testing, it would go to production with a backup of the files that we would put back as soon as we notice something was broken or off.

We used symfony and sonata admin was part of the bundle.

One day, boss asks me to show all the items in a table on the admin page instead of 30 rows.

Me being good guy intern say "sure no problem" so after finding the magic number, I set it to 0 instead of 30.

I gave my work reviewed by my supervisor (senior dev there) and he approved it.

I try to upload the file over FTP. No permissions.

Ask the other dev what it's about, his response: "no idea"

So he tries, fails and decides to try SSH.

Somehow, after fiddling for 20 minutes with ssh, we managed to upload the file.
As soon as we did we hear a scream from the boss's office, we refresh the site, and no matter what page we went to, all we saw was white and the logo of the company in the top left corner.

So this time, we fiddled around with ssh to restore the file for 20 minutes.

Finally succeed all goed back to normal.

A little while later, we call a meeting with the bosses and ask to rewrite the website, BAM, we get approval.

We said "two weeks tops", well that lasted 3 months.

In the end bosses are Uber happy with the work and everything ended well.
Also, development speed has multiplied.