One of my first jobs out of highschool was a retail job that required a lot of customer interactions (specialty store). I worked there through most of college and now, literally decades later, I still find I have to restrain myself from helping other shoppers who have that “I need help” look.
The best for me was about 5 years after I had moved on from the job, I was in a similar specialty store buying something, and one of the customers that I used to help all the time at my old job saw me. She recognized me and her face lit up like she had been saved. She came over and asked me about something that, thankfully, I knew a fair bit about. And then I spent the next 15 minutes helping her out. When she had everything sorted out I walked to the register with her and we got in line to check out. After she checked out, I put my two small items I’ve been holding on the counter and the employee rang up my purchase. The person I had been helping watched me get out my wallet and start paying for the items, got a very perplexed look on her face, and asked me “wait, don’t you work here?” I shook my head and the look of absolute mortification that crossed her face made me both want to laugh my ass off and give her a hug and console her at the same time. She was like, “I thought you were just waiting to help me put this in the car!”. I told her I was going to help her put it in the car, I just need to buy my stuff first. She was so embarrassed, I wasn’t even wearing anything like the store employees, she was like “I thought you were a manager now!”. I told her nope, I don’t even work retail anymore. When she asked why he didn’t say something to her to let her know, I told her that I knew what she was asking about, and that she was one of the really nice customers that I enjoyed helping at the old job, so I helped because I wanted to.