Alright, well. I've just finished the main quest and for this playthrough I decided to then do the fighters guild.

So when I went and tried to join, some of the people think you're not 'worthy' enough even when everyone should know you everywhere BECAUSE YOU'RE DRAGONBORN!!

It makes no sense, many other NPC's act like they've never heard of you and some still try to act tough against you....

Is there a mod that makes it so when you finish the main quest everyone knows who you are? I forgot this one guys name but the guy sitting next to skjor even said "I haven't even heard of this guy, are you seriously accepting him in?"

Like seriously? It isn't just then either, many of NPC's still treat you like [censored] and only the main characters of a certain quest are like "WOAH, I WILL SHINE YOUR BOOTS"

Idk... I just want it to be more 'realistic', ya know?

There are several mods that alter dialogue in areas depending on your achievements so far. Search Nexus and/or Steam Workshop under NPC;s or dialogue. I usually get an assortment of "I'm watching you ..." generics followed by, "Are you really the dragonborn ...?".

However, if you haven't done much in some area, though, don't expect a ticker tape parade when you ride into town. Realistically, and role playing wise, these townsfolk are not considered world travelers so it's more of "what have you done that I have seen with my own eyes?" This may shave your ego a bit, but the individual town quests may not work correctly if the vanilla hooks are fiddled with too much.

That goes especially with the Companions quest line. The first two quests or so on joining are related to "proving yourself". If it helps, role play a little and consider that the current members are ego driven themselves. Dragon slayers don't hold much prestige compared to their high opinion of themselves.