The (slight) downside is that I unfortunately have a dark sense of humor and a sharp tongue that I need to keep in check.

I hear you there. The more conscious I've become of humour the more I realize how dark my sense of humour is. For instance, if anyone plays Cards Against Humanity with me they'll quickly find out that jokes involving child abuse typically trump everything (or decent usage of 'object permanence' I can't tell you how rare it is for anyone to get a joke involving it without me explaining it to them.)

It has helped me get hired, it has helped me get promoted, it has helped me when speaking with people from different backgrounds, it has helped me when I have to speak publicly, it really helps me when I socialize with people I barely know.

I suppose it has helped me in similar ways too. I went into a job interview for a minimum wage customer support job and ended up getting a second interview for a job that payed twice as much, partially because I made my interviewer laugh. I was talking about sales and just said, "Sales isn't like a jedi mind trick, you can't just go, 'This is the product you are looking for'" while waving my hand.