Managers aren't going to hire you if you don't show a passion for a job's core skills. That means that if the position entails developing data processes and programs with Python, you need to know at least the language's basics. If you're applying for a UX position and have never created wireframes, don't be surprised if you don't get even a phone interview. How would you convince a manager to hire you without his preferred skills? Tell us by posting a comment below. Why do companies think this way? One team lead I spoke with put it very well:

Our company is all about Linux. We want people who are passionate about Linux. If someone doesn't even know the basics, well, it's hard to see how they have the passion we're looking for.

That doesn't mean you have to know everything. This manager's company will train people who need to learn Linux's advanced features or areas they're not experienced with. "We invest a lot in training," he said. "But we'd expect an interest. So know the basics." This is where some people start to huff about training. They've got other skills and a solid track record, so why WOULDN'T a company just bring them on and teach them? They've never worked with Python,  but they  know C++. They don't know wire frames, but they're good project managers. All the company needs to do is make an investment in time and maybe a course or two, and they'd be ready to go. Alas, that doesn't solve the manager's problem. He's opened up a job because specific things need doing. While you're being trained, the job's still not getting done -- or it's getting done slowly -- and other staffers are taking time away from their work in order to get you up and running. When you're looking for a job, the bottom line is this: It's up to you to get the training you need to qualify.