A good way to remember it is to use a backronym:

e.g. - example given

i.e. - in effect

i.e. - in eother (words)

in explanation

As someone who was perplexed, I've only heard perplex used in past tense (I was perplexed) so seeing "For the perplex" just made me confused as to what "perplex" meant and I had to do a further search to decipher this tree of comments haha

Ha, ha, sorry. English is not my native language.