Worst enterprise software experience... I was fresh out of college, and needed money. I was working in a call center, fielding IT helpdesk calls for a major US telecom company, who had just acquired a competitor. One day I got to work and about ten of us were given a new desk, new phone number, an an email address at the newly acquired company. My manager said to us "We have no clue how any of their proprietary systems work, what servers they run on, or how to login to them. Your phones are ringing, make sure you take good notes so the Tier-1s can help out next week. Good luck."

Trial by shit-storm fire, all while trying to convince the caller that yes, I did know what I was talking about. It was a lot of cold calling random employees whose job title in the corporate directory looked even remotely close to somebody I could escalate a ticket to. They didn't use the same ticketing system we used, so it was a lot of copy/pasting between two ticketing systems. To this day, I still have no clue what happened to their original call center staff. I'm sure they must have had one, but it seemingly just dissolved overnight.

That job was the springboard to my development career. I left for a gig in software helpdesk, then to quality assurance, automated testing, and now I'm a senior DevOps engineer. It was worth it.