UFC's Conor McGregor -- We Don't Have Lucky Charms In Ireland ... It's Garbage!

The only thing UFC badass Conor McGregor might hate more than Jose Aldo ... is Lucky Charms ... telling TMZ Sports it's not only NOT popular in his home country ... but it's TOTAL CRAP!!!

McGregor -- who's fighting Aldo at UFC 189 in Vegas in July -- was out in L.A when we asked about the cereal trends back in Ireland ... and Conor told us the "magically delicious" cereal couldn't be further from an authentic Irish breakfast (shocking, we know).

Plus, Conor says ... "I don't eat those sugar filled pieces of garbage."