So here is a question I get asked fairly often, "What's the difference of temperament with a pure bred and mix?" Well the simplest way to explain is the pure bred are more predictable, not to be confused with how they are trained, because training makes up for most of your dogs behavior, but personality traits, and basic behavior similarities.
Mix breeds are a bit more unpredictable, there are mix and muts, mix you will find is linked with designer breeds, muts are your rescues, or stays.
Mix breeding is 50/50 breeding and the pup will end up being like one or the other of its breeding.
Muts can be a wide verity of a mouthy lab, aggression of a pit, sweetness of a dane just to be an example having 2% to 10% of multiple breeds.
If you are looking for a set personality trait I would recommend reading up on the different breeds and their personalities. You can never go wrong with a little research before you decide, because pets aren't supposed to hop from home to home, but go to the perfect fit, so that they can live a happy, healthy life.