Mazie is right at three lbs, and is very lanky and bird-boned and "fragile" seeming.
Kiki is right at five lbs, and is very broad and compact and sturdy in build.
The other day my husband picked up Kiki and sd., "Kiki, you are a MONSTER compared to Mazie!" (she doesn't mind...she likes being big and tough!

)
And it's true, she DOES look huge compared to Mazie....and then sometimes I look at her by herself, and think, "Omigosh....she is actually a TINY little dog!!!"
It sure is easy to lose your perspective!
Like some have said, even a ten lb dog is still VERY small! Good grief, we have a cat that weighs 16 lbs!