I began cracking my toes a while ago, but one day, the toes on my left foot began to hurt when I tried to crack them... Whoops! I'm somewhat concerned now, 'cause I can't stop trying to crack them despite the discomfort! (it irks me not to do it) What happened?

I'm not sure about the pain, but I'm addicted to cracking my toes, knuckles and neck.. Based on your question, I feel like we may need a support group to get over this habit, it's like second nature to me.

You know what they say... Once you try crack, you won't go back.

I did see a documentary which mentioned that cracking joints was caused by harmless air pockets or bubbles... More research into the side effects may be required here.