I mean the likes of Pomeranian, Spitz (that's my pet), Chihuahua, Pug, etc.
As for practicality, well nginx explained it pretty well. It's all about your lifestyle and the dog.
Remember an unhappy dog is just next as bad as an unhappy person. They should never be left frustrated, a big dog may very well be so if doesn't enough space or walks. This frustration can be expressed in a variety of undesirable ways. I would personally not recommend those big breeds unless you live in a "haveli" or your family lifestyle involves a lot of walking, particularly if it's the first dog you are going to adopt. Their diet is also a challenge.
Mind you small dogs are not devoid of problems. The beautiful hairline of Spitz and Pomeranian can be really be a problem, and even with regular grooming, they will shed hair particularly for few weeks annually or semi-annually. And as the hair gets suspended in air, I am sure I've eaten a lot of my dog's hairs.
Also remember Dogs can be very moody, and far more intelligent than humans give them credit for. They also have long memory. Only dog owners realize that.