Once you figure them out and learn how to deal with them, they are actually quite simple. Their thought processes are straightforward and even-keeled. What you get one day is unlikely to change the next. If they were gymnasts, they would score consistent 9.7s across the board, every day. Females go from 10.0s to 8.4s, all in the course of one sequence.
Males tend to be more pushy and dominant, females tend to be softer.
Males tend to like to cuddle more, females can go from lap dogs to hermits in a matter of a short time. Males tend to be more physical with their actions - if they want your attention, for example, they come up and nudge you. Females find some other way to get you to pay attention, like doing cartwheels off the furniture or stealing trash from out of the can. Males use their body to get what they want - females use their minds. Most of the problem dogs in rescue are females.