I usually have some decent stories, but when it comes to MIL I got nuthin for the most part. She and I are pretty well aligned on most things, so there is no real issues. Even anecdotal happenings have been slim as her life was mostly focused on my FIL and keeping him alive. Most I can say about her is that she does have her quirks - one of those OCD control persons having raised her retarded brother (yes, literal, like lived his life in a nursing home mostly) from her early teens pretty much on her own until he passed away, and taking care of my FIL for 30y past his first round of heart attacks. As a lifelong caregiver, she's always had to be in control and ensure things follow set patterns, so even today with nobody else to care for she's wired to where dinner has to be not too early, but not too late (think 6:00-6:30), grocery shopping is done on Fridays after work, she has to clean the house on Saturday mornings before the cleaning lady comes (yes, one of those types). Great heart, always means well, and is cognizant of her own crazy enough to let my wife and I raise her grandkids without much back seat comments. Honestly, a really good hearted woman and I can't complain.
Now, if I flip this a bit, my wife could share some decent stories about my mom, her MIL, that make you wonder wtf. Again, good heart, twisted and deep thread of crazy, but nothing of real note other than a short temper that explodes quickly when it goes...but it doesn't go often.