My parents have a Boston Terrier named Millie. She is very well crate trained, and does fine being alone in there all day. HOWEVER...do not be fooled by the Boston Terrier's small size!! Millie is an absolute BRUTE at times, and packs a whole lot of power into a fifteen pound frame!! Millie barks a lot, jumps a lot, and can be very possessive. She is also a very dominant dog who bullies all the other dogs in the family (mine included); on the other hand, she is also a "paper tiger" of sorts, afraid of cars, windows, plastic bags, and other miscellaneous silly things......she is a VERY active dog, though, and a real handful for my parents to deal with!!

Of course, it would be foolish for me to generalize that all Boston Terriers act this way, based on having known only one. But if you are looking for a docile and mild-mannered dog, you might want to consider other breeds!! Just my opinion; no offense to anyone here who owns a Boston!!