Worst one was in my first ever web developer job. It was a small company where everything was done in Adobe ColdFusion. Was there for 2.5 years before they went bankrupt and I got made redundant.

So when it came to look for another job, I was hoping to get another ColdFusion related job. But a lot of company's requirements were pretty bullshit. Junior position, but must have 5 years experience.

After 4 months of looking, eventually found another job but as a PHP developer. But since my PHP skills were beginner's level, I had to start from a new graduate level salary all over again. Felt like the past 2.5 years at my first job was a waste of time.