60-year-old employee excludes coworker from eating with her at lunch, gets angry when coworker makes friends and eats with new hire: 'Too old to be acting like this.'

How are you in your 60s and still acting like you're in high school? 

Some people never grow out of that high school mentality. In fact, many people grow into it as they age. Maybe they never got to be the popular girl who excluded people at her lunch table. Maybe they were the nerd who ate lunch on the emergency exit staircase and prayed that nobody would walk in on them spending the one social hour of the day by themselves. But all of that changed when they became adults and found a working environment that suited them better than a high school. Or perhaps, they stopped being an ugly duckling when they were 21 instead of 16, and felt more confident and powerful. Whatever the case may be, some adults take the opportunity to be the mean girls they never could be in high school. In high school, you're more likely to get in trouble for making fun of your peers than you are at an office job or in an adult recreational sports league. Also, adults are less likely to change than kids. A high school mean girl might see the error of her ways as she matures, but if someone is a mean girl in their 40s and has been for years, the chances of them making a big change grow slimmer and slimmer over time. The mean girl in this story is in her early 60s, so suffice it to say, she is not going to change anytime soon.