COUNT AGAINST = is something negative
- I don't have much experience in this job and this will count against me. I don't really expect to get the job.
- Of course he didn't like you! All those lies you told him certainly counted against you.
- One mistake won't count against you. Just make sure you don't make too many mistakes.
- The fact that you don't speak any foreign languages might count against you in this job interview.
- Your family will count it against you if you don't help your sister.