Does anyone else have a really hard time keeping a straight face when their toddler misbehaves and needs disciplining?

Tonight, LO (18 mos), SO and I were having a "tea party" at her little table in her room and she was serving the pretend "tea" (it was nothing; just an empty toy teapot and toy teacups...) and kept refusing to give Daddy any, and if he tried to get some, she would snatch away the teacup and either pretend to slurp it up herself whilst eyeing him with a sassy attitude, or grab it and be like, "No! Mommy!" and give it to me instead, smiling haughtily all the while. She has a natural tendency to be kind of a miniature Regina George and it worries me but for the life of SO and I, we could NOT STOP GIGGLING to seriously try to change her behavior!!! I keep finding myself laughing uncontrollably, and it's horrible because I'm sitting here wondering, is this why some kids are mean bullies? Because their parents couldn't stop laughing so now they think being mean is funny? I know we have a lot of time still to guide her down the right path but it's SO HARD when the level of sass is just way out there for that tiny little person to have! What do you more in control parents tell yourselves to stop the insidious giggling? via /r/Parenting http://ift.tt/2CQA69f