25 of the strangest things people have done in a job interview

For instance, according to recent surveys from CareerBuilder, one interviewee sang her responses to questions, while another did a phone interview in the bathroom - and flushed.

"It's hard to say why a candidate would do some of these things," Rosemary Haefner, chief human-resources officer for CareerBuilder, tells Business Insider. "Maybe he or she is nervous, thinks an employer would find it funny, or perhaps the candidate simply has no boundaries."

"Regardless," Haefner says, "it could cost the candidate the job, so funny or not, it's likely not worth risking it with these actions. Your nerves can make you freeze up under the spotlight, and that's normal. How you handle that is what matters."

More than 2,600 hiring managers and employers shared with CareerBuilder the most memorable job-interview mistakes candidates have made. Here are 25 of the most unusual things that happened: