The first? Pokemon.
To this day, people are horrified that I didn't watch the show, didn't trade the game cards, and didn't EVEN play Pokemon on GameBoy (Yes, I missed out on GameBoys too. At one point, I think there were more GameBoys in the playground than children).
I get the premise of the show, and I actually played the game on GameBoy for the first time about a month ago - to nobody's surprise, I was terrible at it!
I also missed out on Scoubidous.
Remember those plastic strings that kids weaved into little key chains and bracelets? Well, one day, I walked into school, and every child was devotedly weaving away, except one - me. They got banned pretty quickly at my primary school because the children kept whipping the backs of each other's legs with them, but for about a month, those Scoubidous were just about the coolest thing around. My parents did eventually get me some, but about three months after they were cool. Jeez, Mum!
Lastly, I never owned a Tamagotchi.
In retrospect, I'm kind of glad that I didn't have one. Tamagotchis were these little electronic pets that you had to feed, put to sleep at night, and water - in short, they seem like fairly stressful toys.
I vividly remember kids at my school crying that their beloved baby "Tama" had died in the night, or accusing their friends of killing them by pressing the wrong buttons. In fact, I read a really interesting article a little while ago about how lots of children experienced full-on grieving for their dead Tamagotchis, and some actually had to have grief counselling! Scary stuff.