Help me just 'let it go' re mil

[bingisthebest]

Mil helps us with childcare. Good grandparent. But she just irritates me so much. Lots of little things. Always turns up really early, never relaxed situations. First to anything re kids, e.g school plays. So early it would be virtually impossible for me to be there before her. Never gets cross. Says 'mummy said no' never a no coming from her. She is on her own, we are main family so I feel the responsibility but sometimes I wish it was just us, our family of 5.

We've just gone out all together. Turned up early so in stressing trying to sort kids. Doesn't help really. Then out puts her bag on the buggy and gets huffy when I try to push the buggy. Has to be in the front seat.,. blah blah. I know I sound like a twat.
I am aware that I am probable being very unreasonable. So help me to just get over it. Every time I'm with her I tell myself to not be a moody cow but I endup bring snippy then feel guilty all day as she's now at home alone.

I think my dh feels like this about my mum sometimes. But, they live 150 miles away so it's not often.
We always let grandparents sit in the front, it isn't comfy between two car seats! If one of us has 2 grandparents and 2 kids, the skinniest grandparent gets wedged in the back, usually only for short journies.
We had an overbearing relative. We decreed every other Sunday as our own family day (ie our household) but used to break the embargo for fun friends!

As pp I am different with my mil than anyone else. I guess I don't like her happens to me when I'm with her. I guess I find having young children stressful a lot of the time and she obviously is present at a lot of these times therefore adding into things, making me feel more stressed! And then it's the guilt. She does have a few friends but no hobbies and doesn't do a lot else other than garden. My parents are busy and occupied so I don't really worry about them. But mil does get lonely so I feel pressured to constantly invite her to things. So lots of factors.
Thank you for all the replies. I've enjoyed reading all of them thanks.