Medium Access Control (MAC) delays significantly increase the packet service-time in saturated networks. As the number of contending nodes increases, the occurrence of collisions and cross-transmissions (CTs) also increases, resulting in high packet service-time. In this paper, we model packet servicetime in IEEE 802.11 Distributed Coordination Function (DCF) networks in terms of medium access delays, and illustrate the impact of collisions and cross-transmissions on the neighbor's transmissions. Our simulation results indicate that collisions and cross-transmissions induce high delays in the packet-transmission process severely degrading the performance of the network. We conclude with a discussion on the effect of packet service-time on the real-time applications.