Unpredictable

Dogs are unpredictable. Which is why people like Kenneth M. Phillips exist.
https://dogbitelaw.com/dog-bite-statistics/all-dog-bite-statistics
"Dog attack victims in the US suffer over $1 billion in monetary losses every year. ("Take the bite out of man's best friend." State Farm Times, 1998;3(5):2.) That $1 billion estimate might be low -- an article in the Journal of the American Medical Association reported that, in 1995, State Farm paid $70 million on 11,000 claims and estimated that the total annual insurance cost for dog bites was about $2 billion. (Voelker R. "Dog bites recognized as public health problem." JAMA 1997;277:278,280.)

Dog bites send nearly 316,200 victims to hospital emergency departments per year (898 per day). (Holmquist, L. (Thomson Reuters), and Elixhauser, A. (AHRQ). Emergency Department Visits and Inpatient Stays Involving Dog Bites, 2008. November 2010. Agency for Healthcare Research and Quality, Rockville, MD. http://www.hcup-us.ahrq.gov/reports/statbriefs/sb101.pdf)

There was an 86% increase in hospitalizations because of dog bites from 1993 to 2008. The number went from 5,100 hospitalizations in 1993, to 9,500 in 2008. The average cost of treatment was $18,200 per patient. The patients generally were kids under 5 years old and seniors over 65. (US Dept. of Health and Human Services, Hospital Admissions for Dog Bites Increase 86 Percent Over a 16-Year Period, Dec. 1, 2010.)"