When I have a bad day at work, I think of Serena Williams. I tell myself that if she can do her job then I can do mine. To be clear, I am not a professional athlete – I struggle to walk up more than one flight of stairs without losing my breath. And, no, I’m not the mother of a small and adorable child, I just about keep my houseplants alive most weeks. The thing Williams and I have in common is that we are black women who work for a living. And being a black woman at work comes with a specific set of challenges.

Black women aren’t allowed a bad day at the office. Or to be precise, if we have a bad day we can’t usually risk expressing anger or sadness about it. So many of us develop a work persona that allows us to get ahead in white workplaces. Mine is incredibly smiley and friendly. When I have an office job I tend to make lots of tea, I am sociable and supportive and lots of fun at a Christmas party. The few times I adopted a different persona did not go well. A couple of years ago I disagreed with a male colleague’s idea and he pulled me aside to tell me I was being aggressive. When I attempted to explain that the word aggressive is racially loaded he burst into tears. It reinforced a lesson I learned throughout my 20s: most of the time it’s not worth trying to explain racism or sexism at work. Just get your head down and get the job done as best you can. If you are not a black woman and are confused right now here is a two-minute video about intersectionality.

Williams is an inspiration to me because when she has a bad day at the office everyone in the world knows about it. At the weekend she lost her temper at an umpire she perceived to be behaving in a sexist fashion – punishing her when he would merely have warned a male player. Not only was she docked a game, she faces a fine, and weeks of media attention about how she behaved. Can you imagine sending a shirty email to a colleague and having wall-to-wall media coverage about your curt sign-off for the next three days? Can you imagine confronting your least favourite person at work and then seeing a photograph of your facial expression on the front page of every sports section in the world? What would you tell your child about the racist cartoons she will find when she gets old enough to Google you? I have no idea how Williams does it.

We only see a fraction of the discrimination high-profile athletes such as Williams experience on a daily basis. Any woman who works knows that you have to develop a pretty thick skin to handle the dozens of small instances of everyday sexism. That showing authentic human emotion risks you being labelled “hysterical”. Those of us who feel secure in our jobs or have nice colleagues have an easier time of it, but remain painfully aware that not everyone is allowed to make mistakes and stay employed. If you have faced discrimination of any kind at work, this video of Williams talking about the US Open is hard to watch.

The most surprising thing about the US Open is that the chief executive of the Women’s Tennis Association, Steve Simon, backed up Williams when she highlighted the sexism of the umpire. It reminded me of all the times I spoke up and wasn’t alone. It made me hopeful that tennis might become marginally less sexist. I only wish change came at a lower price for women such as Serena Williams.

• Carys Afoko is the executive director and co-founder of Level Up, a community for feminists who want to work together to end sexism