Megumi has a very cheery personality and likes to have fun whenever she can especially around Kuruyukihime. Since being close friends with Kuroyukihime, most of the time she addresses her by a nickname "Hime" which would mostly like be her name shortened.
However, during their time in Okinawa, it is revealed that she can become quite depressed as she stated to Kuroyukihime that she is lonely more frequently when she is not around her as she seems to spend more time in a different world (Accel World) than Megumi.
(Source: Accel World Wiki)