Supervise your dog. EASY Stop giving him food when he begs. A behavoir will be extinguished when it no longer reinforces itself. It's close to 30 years for them. They are very sensitive, very delicate, and not very tolerant with children.
Pugs have a wonderful temperment.
Actually, some Shitzu, but be careful of the lineage. Some can be aggressive. Definitel yask the breeder what his temperment. Papyons tend to be much more tolerant than Pekinese as well. Terriers in general can also be Terrorizers.