I see no point in mincing words here: If you're an at-will employee — as most of us non-union members are — you can get fired at any time for no reason at all (so long as it isn't illegal). That's a fact.
But assuming you don't work for an organization that's likely to ax you for well, doing a great job and garnering high-performance marks, you probably don't need to overthink this one.
More from The Muse:
Why getting fired was the best thing that ever happened to me
The hard conversation you need to prep for if your job's on the line
How to handle yourself at the office when a co-worker suddenly loses his job
With that out of the way, let's talk about some common reasons people lose their jobs (and I'm not talking about unavoidable mass layoffs or inability to meet a clearly defined sales goal).
No, I'm referring to those altogether avoidable things that you have no business doing — unless you don't care about getting let go.