Whats the biggest Hang up with PBP games?

For me the one feature that keeps me in the game is email notification. in the yahoo game I played the daily digest of the post to the yahoo group hit my email and automatically kept me upto date. The GM did his weekly post on Sundays and I got in the habbit of religiously checking my email every sunday morning like reading a Sunday paper. Usually had a response post done before going to church.<br /><br />Later I joined Beowulf's Lost Worlds New Frontiers game and had a hard time keeping up- easy to be distracted and forget to check the game (no email notification) as you had to be real good about checking the site weekly. Same with Terl Obar's Obar Enterprises game. Some how I guess I just need to create a schedule that reminds me to hit those games.<br /><br />As for running a game- loss of a job and starting a new one disrupted that- time went by and now I just have a twinge of guilt for a game left unfinished.<br /><br />So what keeps you from playing a PBP?