I always thought it was strange that Mecklenberg is more Democratic (by a significant amount) than Wake. Just looking at the Demographics and population you'd think Wake would be the Democratic stronghold and Meck would just be a lean Dem county, but they're both becoming Dem strongholds.
I think Mecklenburg is more Democratic than Wake because Charlotte contains a larger share of Mecklenburg's population (79.8%) than Raleigh's share of Wake's (44.8%). Raleigh is probably more liberal than Charlotte.