I've always found accents interesting, but as a non-native English speaker I am having the hardest time understanding someone with a heavy accent on the phone.
Add to that the fact that I talk really quietly, and you get this every time:
Person: "Yes, hello, this is *krkaarkr* calling from *rapid-fire slang*
Me: "...I'm sorry, what did you say?"
Person: "I am *slursluslur* from *accent deeper than the Marianas Trench* calling about your *garblegarble*
Me: "...."
Person: "..."
Me: "I'm so sorry...no?" *click*