I have never had any first hand bad experiences with a pit personally, but my friend had one that "wouldn't hurt a fly" snap one day after 12 years of zero issues. He told me he got up from the couch and was walking to the kitchen to put his dinner plate in the sink and his dog was eating at his food bowl. He said he walked past the dog, and then out of nowhere the thing latched onto his calf and damn near tore his calf off before his wife could bring him his 9mm. Damn thing took 6 shots before it stopped... 2 surgeries later and he still can't walk right. I guess some are just a ticking time bomb.