I remember going in for an interview and they gave me 3 sheets to work on:
1) Math 2) Logic 3) Programming Language
I am terrible at math and did not do well on it. It was like formulas, calculus, and trigonometry. I've never even used that stuff for the programming language they wanted to ensure I knew. I warned them too. But I did ace the logic and passed the programming language sections. Happy the company took a chance on me. Haven't had an interview like that since but I'd probably be the one who would fail most interviews where I feel I am under pressure.
To make up for this, if I ever did have to go in for an interview at a job, I've already prepared myself with a profile of web applications I've built and the Internet uses for their pleasure or business. Might not be perfect, but it at least shows I can do something. Hopefully the company hiring me would take that into consideration.