When your child suddenly drops on the floor flailing over you not letting him play with a Sharpie. When your child pulls your hair or slaps your face and you just want to lose your cool (or you do because we are all human). When you tell your sweet toddler it's time to go and they bolt in the other direction. <Sigh>
Our third child hasn't been a super angelic, innocent, I want a fourth baby right now just like him child. The almost two or 2-3year old phase is the hardest because they can't fully communicate their feelings and their frustration drives them to do the silly/stupid/ridiculous things like biting, hitting, tantruming on the floor. I'd like to think I have the patience of a saint but we all have our limits.
Laughing helps a lot, but so does ignoring, timeouts in his room (which until recently he couldn't open the door to get out), or redirection/distraction. Hang in there this too shall pass!