Two important points:

1. Know when an interview is appropriate. Interviews aren't the best way to gather facts, but are great for gathering opinion. People's memories of facts may be faulty, so rely on other sources when possible.

Your contribution to any work group is dependent on two things: your abilities and what the group expects from you. You can only control your own behavior – period.

However, there are a few identifiers to self-centered, negative influencers.