These are two different verbs: one means: to be positioned horizontally (lie) and the other to position something else horizontally, to put something down (lay)
They sound similar and have a meaning connected to being horizontal, that's one reason for their confusion.
Make sure you also don't confuse their past tenses:
Lay: laid
lie: lay
Yes, Lay is the present tense of one of them and the past of the other: that's the other reason for their confusion!
I believe "You will eat lunch / at school / with friends" most clearly develops an argumentative tone because of the 'will'. Sounds like someone's trying to force the person to do that and the person may try to argue back because the will makes it sound like they have no choice in the matter.
