XYZ's aren't even that stupid as a concept, some of the cards are obscene. Pendulum summoning is so bull**** they had to create a new space on the game board to make them. Someone thought it would be a good idea to make a mechanic that lets you dump your entire hand full of monsters (and all the pendulum monsters that were destroyed/removed in the possess of setting up) onto the field, and then doing any number of synchs/xyzs/effects/attacks you feel like. Its not too bad because it is litterally putting all your eggs in one basket, but god damn is it stupid.
ex: I had a really long duel against a pendulum deck on a simulator, I had 100% control the entire duel until I ran out of MST's and he got to pendulum summon on the 17th turn or something (his archetype has a lot of floaters that keep comming back from the grave, my deck just blows it all on one indestructable beater [can only be removed by battle with a monster with 3500+ atk. or banishes or bounces that don't target] so it took forever). He summoned his whole hand, tributed it for the legal Obelisk, and the summoned everything again somehow and OTK'd me.
Yugioh is stupid but enjoyable. I like how the Decks are really consistent (my only gripe with Magic imo).