Usually when I hop on a call with someone from whom I am trying to learn, I have done enough background research such that I have a loose grip on the topic. Alternatively I have done plenty of networking calls with younger people (usually college students) who very clearly put in 0 effort ahead of time.
Yesterday I had a call with a guy who has worked in the CPG space for a long time, and I very much felt like one of those bewildered college kids trying not to come off as a moron. Luckily he was a nice guy but still, pretty embarrassing on my part.
Noah's (Life) Ark 