The most common question in minds of students going for F-1 visa interview is - are some visa officers lenient than others? The clear answer is NO, because every visa officer considers every case coming to them as equal and never differentiates between the candidates. The smallest of the factors which could come in picture in the rarest of the rare cases is the good day or the bad day of both the interviewee and the interviewer. Since these external factors can't be controlled, so you should always give your best while being interviewed for your visa application, without any inhibition.
Have a look at this short video by Mr. Patriek Karayil, to get a better understanding on this common concern among students. Patriek, an MIT graduate and a Former Vice President of U.S. News Global Education, has worked with over a dozen U.S. universities and has counseled thousands of students and liaised with U.S. embassies and visa officers. He is considered as one of the foremost experts in U.S. Education for international students.