There are some behaviors that you can just expect from toddlers:
dumping. You can pretty much expect that if you have a bin filled with, well, anything, that a toddler will want to empty it. If it's a big bin, it'll be a one-by-one proposition. If it's small enough, it'll be picked up and overturned. Fortunately you can usually get them to put the things back in (although, it does become a bit of a game — throw two items out, put one in, throw five things out, put one back, etc.). Which brings us to another common characteristic of toddlerhood:
distraction. Oh, look. Here's a book. Let's look at it (thereby forgetting to put things back into the bin — but, on the other hand, also forgetting to throw things out of it!).
And another very common behavior:
climbing. The world looks so much more interesting from a higher spot. (And, having a good ledge to chew on is nice, too...)
Oh, and removing clothing — especially shoes. If they can get them off themselves, they probably will!
So, the message to parents of toddlers is — this is a very brief time in your child's life. Encourage them to do what you want them to do (keep the toys in the bin, keep their feet on the floor, etc.), but be patient as they really are learning a lot through doing what comes naturally. And, whenever possible, use that tendency to be easily distracted to your advantage!