Guy's mom shows favoritism to 'adoptive' neighbor; he walks out on her. AITA?

AITA for leaving when my mom told me to move my car so her neighbor’s daughter can park in her driveway?

Some backstory: my mom has always wanted a daughter. Instead she ended up with 2 sons and 6 grandsons.

16 years ago, a young woman with a 2 year old daughter (let’s call the daughter Lily) moved across the street from her. She was a single mom and didn’t have any family in the area so my mom offered to help take care of the little girl while her mom worked/studied.

Over the years, she’s become an adoptive mom/grandmother to this woman and her daughter. She was there when the woman married her husband and had 2 more girls together. She’s very close to the whole family but especially Lily.

My mom was born and raised in Italy. My dad was French. My brother and I don’t speak any French or Italian. Lily is not only fluent in French and Italian but she knows more about the culture than me or my brother and she knows all of my mom’s recipes. My mom also helped pay for her private school tuition because she doesn’t like the public schools in the area.

Lily, my son, and my nephew graduated from high school in may. My son and my nephew each got a card and a check for $300. My mom took Lily to Europe for 8 weeks over the summer.

I got to my moms house with my sons last night. We planned on staying for a few days because we live 8 hours away. I was parked in the driveway, then right before dinner my mom told me I needed to move my car so Lily could park in her driveway.

I said Lily could park on the street but my mom said no, the driveway is Lily’s spot and I have to move so I told my sons to get our bags and we went home.

My mom has been calling me since last night asking me to come back and saying I overreacted to being asked to move my car. I refused and my sons and I are celebrating without her but I’m starting to wonder if I was the asshole for leaving when my mom told me to move my car.

Edits & Info from OP:

It’s my mom’s driveway but apparently it’s Lily’s spot. My mom parks in the garage.

My kids went to public school. I didn’t even know she paid for Lily’s tuition until recently and she excused it by saying I live in an area with good public schools and I make too much to qualify for scholarships so she’d have to pay $10,000 for my sons compared to $2,000 for Lily.

She and Lily drive each other to appointments, Lily took her to buy a new phone and an iPad because my mom doesn’t understand technology, she helps my mom set up doctors appointments online and manages the dog’s grooming appointments because she messages the groomer on instagram and my mom doesn’t have an account.

Besides that my mom is very independent. She goes to workout classes at the senior center multiple times a week, she volunteers at church and the community garden, and she’s always doing various projects around the house.

From the comments:

mochimmy3 writes:

OP was a fully grown adult having his own kids when his mom met Lily. Maybe things changed. Maybe when she was raising OP she was working full time and now she’s retired and has more time to teach.

StatedBarely writes:

Yup to all you said.

Also mom probably had an empty nest by the time Lily came around. Her boys are all grown and have left the house. She’s probably retired/semi retired by then and have a lot of time on her hands to look after Lily. Lily and her mom probably treats the mom really well and have become family.

painted_unicorn writes:

NTA the whole '$300 vs 8 weeks in Europe' really sealed it for me. What blatant favoritism, this isn't about a parking spot, it's years of built up issues.

BurdenedMind79 writes:

The phrase, as I learned it, is 'the straw the broke the camel's back.'

The 'straw' (parking spot) isn't the problem. Its everything else that was piled on beforehand that had things so close to breaking. This incident was simply the point where you can't take it anymore.