Struggling with apply() in R

It’s common knowledge that I struggle wrapping my head around the apply functions in R. That is illustrated very clearly in the following discussion on Stack Overflow: Dirk’s comment is actually spot on. I’ve asked the same damn question at least 4-5 times. Only I didn’t really understand it was the same question. That’s one of the problems of not really being good at something; it’s hard to think abstractly about it.