“I will do anything.” An employer conducting a job search has a specific need and is looking for the candidate who can best address it. Saying you will do anything does not focus the employer’s attention on you as the best candidate for the position; rather, it suggests that you are desperate for work. Also, suggesting a willingness to do anything devalues the work you have been trained to perform.
“I really need this job.” A job interview is not about what a candidate needs; it is about what the employer needs. The fact that you have two kids in college is irrelevant, and sharing such information suggests that you might say anything to get the job.