There are a lot of things that I have learned from working in customer service.
And no, it isn't the typical "the customer is always right" concept. As someone who is pretty introverted and has a massive amount of social anxiety and anxiety in general, it has not only helped me learn how to navigate working with people - it's helped me come out of my shell and actually be able to interact with people.
Like said above, I am very introverted. I get so emotionally drained just from school that working two jobs on top of that left me wanting nothing but to be home in complete silence, admittedly to a point where I would actually turn my phone off and curl up in bed at seven-thirty. Working retail and as a teaching assistant helped me break past that. It put me in situations where I couldn't lean on my want to be alone as an excuse and made me push beyond the normal measure that I deemed acceptable for socialization. I had to work with my situation, adapt, and make myself comfortable in a situation that was completely out of my comfort zone.
Social anxiety is something that isn't fun to have when you work in retail.
Watching large volumes of people walk into your store while you're the only person there can literally make you want to vomit. That is strictly speaking from personal experience, of course. However, I've managed to deal with the large volumes of people and make friends with some of my regular customers. Having to work nine or ten hour days really made me have to look at how I am taking care of my mental health and adjust to make sure that I don't freak out every time I have to interact with large amounts of people. My tips are taking deep breaths, focusing on one person at a time, and initiating a conversation with each one to release the nervous energy that I'm feeling at the time.
One of the negative things that I've had to come to terms with is that sometimes, you end up in extremely uncomfortable and/or awkward situations, which doesn't help with any of the above issues to begin with. But, they're learning experiences as well. I've had customers ask me out, which got me to feel out how to let someone down easy and in a friendly way. You'll always have the rude or demanding customer, and I've had to learn when it's okay to bend and talk through the situation with them to come to a solution; on the opposite end I've also had to learn how to be assertive and say no, which is terrifying to me still to this day.
Overall, working in retail and with kiddos has helped me learn how to get out of my comfort zone. It's come as a blessing that's very much in disguise, but looking back on it now, I've gleaned so much life experience and made some great friends along the way. While it was painful at times, I'm grateful for the lessons...and income...that jobs can bring.