For me happiness is spending time with Lex watching Pixar movies. Happiness is hearing him giggle when he's doing something he shouldn't or he finds something completely off the wall funny. Happiness is hearing a new word come out of his mouth, even if that new word (bad) is paired with mommy. Happiness is him giving me a kiss or hug to apologize for biting or hitting me.
I've found I've been my happiest lately with it just being me and Lex. Sure things can be stressful, especially when he's slamming his rock hard head into my freshly pulled tooth spot but I am enjoying every minute of my time with my Lexy Lex.