It's not a GMs job to take a pile of random characters, invent reasons for them to be a party, and find hooks for each of you.

As players, you're just as much part of building the game and should work with each other to be a cohesive group of characters and to have story buy-in.

This can become more apparent in non-D&D systems where the group isn't just four heroes on a quest killing stuff for loot and xp.

Sometimes you have to set aside your first choice in character for one that fits better or adjust some aspects of their personality and background.

And that's not to say you can't play what you want, so much as its a reminder that creating a character in a vacuum then showing up and expecting the group and story to make room for you doesn't mesh with the spirit of the game--you're all in it together and part of a team.