Hmmm.. The stamps that increase the Unique drop rate.. I guess I'll go with "jumping for joy" even though I don't always go boss hunting. Something to help gather Boss Weapons since they cost A LOT of billions.
It's just the same as people buying Black Elixirs/Nate Bottles or whatever items you can get inside those LevelUp Boxes. Buying the MyShop Items rather than spend hours hunting for them. Or like selling MS for galders rather than farm for items/cards/equipments to sell so that you have galders.
If there is something that makes MyShop users more hax or more comfortable than Free Players, why should people complain? Free Players sacrifice time while MyShop users sacrifice real money (which can be obtained thru work and thus, still uses time).
But in the end, everything is just about who can spend the most money. Galders, Levels, Hax Equips, all can be bought. Money = Power...
By the way, if you don't like it, don't buy it. Just don't FORCE others to be a saint like you