I have been thinking about a lot lately: Naming, Grammar, Usages so forth. The first thing that came up to my mind was SIMPLE PRESENT. It is usually the first grammar topic ever taught by teacher in much of the world. Nevertheless, it is a little bit more confusing than it is shown as.
Firstly, the name SIMPLE PRESENT or, in British English, PRESENT SIMPLE, leads the learner into a path that should not be taken: the learner believes SIMPLE PRESENT talks about the present events. If you believe so, you are doomed to failure when it comes to its usage.
SIMPLE PRESENT mean ROUTINE, DAILY ACTIVITIES or merely HUMDRUM. That is, we use this tense in order to talk about something that normaly happens.
Julia has lunch at noon everyday. Julia doesn't have dinner at 11:00am everyday.
I have dinner at 7:00pm everyday. I don't have dinner at 6:00pm everyday.
Those words above in bold are the auxiliary verbs, DO and DOES and their respective negative forms DON'T and DOESN'T.
Rodrigo Pelegrini Honorato