Are there no rules to when you can and can not change tenses, using narrative present?
Like, could I say one of these:
I was on my way back home by bus. The guy who sat next to me looks at me weirdly and gets off the bus.
I was on my way back home by bus. The guy who's sitting next to me looks at me weirdly and gets off the bus.
The first one just seems odd. Would it be okay to use it?
Or constructions like:
I was walking with my mother down the street the other day. The whole way she's been holding my hand tighter than usual. I didn't know why she did that. Anyway, we were walking down the street, this car pulled up right next to us and it was an expensive car, I look at it, my mother looked at me looking at it and slaps me.
That whole thing might just be complete gibberish, but is it okay to speak this way? Are all three of the highlighted parts okay to use when speaking?
Best Answer
The short answer is that in good writing, you shouldn't switch tenses the way you did in your examples. Inserting the narrative present into a narrative that is otherwise in past tense has to be handled very carefully with good transitions between. Usually, you want something to indicate that you are now going to tell a story within a story of sorts. And after you switch to the present tense, you want to stick with it for the entire story. For example:
The first sentence sets the stage for telling the story about your experience. Then the experience itself is related in present tense to give it a sense of immediacy. Some writers would insist that you shouldn't make a tense switch like this one, either, but in my opinion it can sometimes be an effective tool (when used sparingly). You might, especially, see it used to relate dreams within a story, for example.
In spoken language, however, people mix up tenses all the time, and I can easily imagine someone mixing their tenses in speaking the way you did in your mother story (although not the way you did in your bus one—that one's too extreme even for speech). But it's not necessarily purposeful, it's just a question of mouth moving faster than brain—and possibly of the person telling the story switching in and out of a personal sense of immediacy. For example, the person is possibly living in the memory of the story when saying "she's been holding my hand tighter than usual" and then coming back to the true present to reflect on it with "I didn't know why she did that."
The reason the bus example feels too extreme is simply that it's just too short to support the tense change. There's isn't a separate subnarrative there. It's only two sentences, and each is in a different tense.