Affect Vs Effect

After reading a couple of poems about spelling and grammar, i questioned about the the correct use of affect vs. effect and had a bit of a play around with a few words. Silent One ... this is for you. :-) Started reading some poems about English spelling and grammar, I brought up affect and effect which threw in a bit of a spanner. Does anyone really understand the difference between the two? I like to think I’ve got it but the truth is I don’t have a clue. I set myself a mission to find out about these two words, What I didn’t realise was, there is actually a third. Affect is to change or cause an influence in a particular event, Effect is when a change has occurred, so that answers that argument. But as I investigate further, when S is added to effect it changes the entire meaning, It means personal belongings, my head now hurts, oh why did I start intervening?