(CNN)Abby Mahler ended a childhood friendship in the comments of one of her Instagram posts.
"You do not get to like this post with (the) amount of restaurants you eat at. [expletive] I mean it," she wrote.
Mahler, 27, has lupus and is immunocompromised. She has spent the past nine months using her social media account to help inform others about the importance of mask-wearing.
But Instagram has also been a window into the day-to-day activities of people who have gone about their lives as if there were no pandemic: eating at restaurants mask-free; going on lavish vacations; hanging out at bars.
So when one of those friends hit "like" on one of her posts, she didn't hold back.
"I have no patience for people who don't think literal rules apply to them," Mahler told CNN. "And for people who don't have an understanding about the disconnect between their behavior and reality."
Relationships, like the one between Mahler and her childhood friend, have been tested during the pandemic.
While the first few months led to Zoom hangouts and remote celebrations, deepening and visible divisions in how people are handling the ongoing pandemic have become the source of growing tension -- and sometimes outright conflict.
Some have said their relationships have strengthened during this time, as they have prioritized whom they care about and how often they check in.
But as 2020 comes to an end, others say distance, as well as differences in how their friends handle the pandemic, has changed their relationships -- and not necessarily for the better.
"A lot of relationships right now are struggling with how people are responding to the pandemic differently," Shasta Nelson, an author and friendship expert, told CNN earlier this year.
They feel judged, she said -- or they feel guilty, or they feel judgmental.
For some, their values no longer align
Like Mahler, 33-year-old Manisha Jogia found herself at odds with one of her friends during the pandemic.
In August, she said her friend had told her he was breaking away from his pandemic bubble to hook up with girls he met online. When Jogia, who is from Los Angeles, called him out, she said he brought up the Black Lives Matter protests she'd attended.