Acknowledging the "terrible twos," however, doesn't make the difficult behavior easier for parents to handle -- actually, only understanding your child's developmental stage can do that.
Remember, a toddler like Max isn't a baby anymore, and since he has to grow up whether he likes it or not, treating him like an infant will only make him balk. But a toddler isn't a preschooler yet either, and since growing up is difficult and scary, treating him like he's older than he is makes him clingy. While his in-between behavior is confusing for you, his own ambivalence is often painful for him. Your toddler has to pursue his own ends even when they're at odds with yours, but conflict feels desperately dangerous because he still loves and depends on you. He needs to be sure you'll go on loving him.
This toddler stage isn't just an awkward phase to be gotten through as fast as possible. It's an important period in your child's development. Over the next couple of years, she has to learn to do as kids do and babies don't, which means changing from diapers to underwear and out of a crib into a bed. She has to be able to eat and drink without special baby stuff like bottles and sippy cups. And she has to know enough playground rules to get along with other kids. Wow! It's a lot to learn.
And then there's the question of independence. Ten years ago, few parents expected babies and toddlers to stay with unknown adults in unfamiliar places. Now many places parents go to, such as health clubs, provide childcare, and children are expected to accept it. The reality is that while some do, many don't. And the fact that some kids will happily play with all those toys, not minding that Mommy or Daddy is going away, makes it hard for parents of the others to accept that it's age-appropriate for an under-3 to protest being left in that situation. They'd like their child to be more independent. If you think about it, though, that's a pretty silly notion. How can someone who can't meet his own physical needs be independent?
Bottom line: Some toddlers are more confident in social situations than others. If yours is a dive-in kid, fine. But if he's a need-to-know-you-first kind of person, that's fine too.