How do you deal with parents expectation mentality?

Learn to say "NO" and mean it. No argument allowed. You and only you control what you will or will not do. The sooner you establish this boundary and keep it enforced, the sooner will you reclaim your sanity. I learned this the hard way. But refusing to argue keeps you in control.

Compromise

You have got to put yourself first. If you have already started doing things that you're not willing or able to do long term, you have to talk to them and tell them that you didn't mind doing things on a temporary basis but you don't believe it's a good long term situation. You have to have your own life, and you need to take care of your own health, or you'll be gone before they are.

This is almost a mandatory problem of caregiving I think. This site gets tons and tons of people with this very problem every day.

Parents & adult kids rarely, if ever, sit down and talk through what anybody wants or needs from each other through the aging process. I know my mom wasn't even willing to acknowledge that aging was happening.

Without that conversation, a lot goes unsaid, assumed, and then expected. There's no shortage of disappointment all around.

Be that as it may, you are an adult with responsibilities and obligations, presumably to earn an income, pay your bills, provide food and shelter to yourself and maybe your own kids, pets, etc. You can't just put that down because mom is aging.

I think a lot of seniors find themselves in an unplanned situation where they do need help, but they fail to understand this is not a temporary thing. The expectation that you'd come to help may be reasonable if it was short in duration. But when the need will go on and even increase until the inevitable end, you can't expect someone to step into that role, no questions asked.

You have to have some very strong boundaries in place and don't feel bad about enforcing them.

I had to be very clear with my mother that she was going to have to see the onsite doctor at her facility. I had used up every bit of my time off at work moving her and getting her settled. I didn't even have time off for my own doctor appointments because of this. Nobody has to like it, this is just the way it is. I'm not willing to take unpaid time off work when there's no good reason to.
The onsite doctors were just as good as anybody else.

I had to establish boundaries about when I was willing to run errands and go grocery shopping for her, when there was a perfectly good shuttle to the same store right from the lobby. Mom, if you aren't going to use the shuttle, then you'll have to wait until I have a few hours free.

Yes, she pouted. Yes, she tried the guilt trip. Yes, she tried wheedling me about my life's details so she could say "SEE - You COULD have come and got me!". She tried to make me feel bad about going on a date with my husband or doing things with my own kids. I dared not tell her about doing anything with a friend. She tried to find out if I was going to have a moment of down time to claim.

A good therapist helped me understand that I was not responsible for her happiness, her sense of fulfillment, or her entertainment. When mom was refusing to eat in the dining room, participate in activities, cooperate with medication, and being a general sour puss, it was not my job in life to run to the rescue.

It was my job to see that she was safe, clean, and fed. I had done that. Anything else was extra. You can run yourself into the ground and STILL feel guilty it wasn't enough if you don't get some life boundaries.

Sandwich42plus really hits the nail on the head. I wish I had her to talk to several years ago when we tried putting my mother in assisted living, and had to bring her home after 3 months. Mom didn't want to play Bingo, sit with others at the weekly music entertainment, eat in the dining room, etc. She didn't make it easy. It didn't make sense to keep her there, but in retrospect, we might have waited too long to transition here in there. She fell 2 weeks into her stay and they brought her to the hospital, then it was a rehab and 3 wks before she got back. A bad start. Downhill from there. It was no easier for me, though we had meetings, etc. to try and help her get acclimated.
I'd also like to suggest that anyone who can get their hands on the book by Roz Chast- Can't we talk about something more pleasant? Read it. It's amazing.

I feel my parents' grabbing me through the telephone, or even in person, after I have spent 4.5 hours taking them to church and out for brunch, they want me to sit with them all day and ino the evening....watching TV. What I have to do is have an appointment with a client scheduled for 2pm, and I have to stop by the distribution center before that (I can't use that one too often). If it sounds like I am lying, yes, I sort of am, but they don't understand if I tell them the truth, maybe I just want to go to my own house and curl up in the porch with cat on my lap and read..... I have to have some "me" time and in their senior condition, they've forgotten that that is not a lonely thing for me, it is a rejuvenating thing. They are so fad removed from hard-working lives balanced with "down-time". Everything to them is down-time and why would anybody want to do that? So I have to invent work time, which is the only acceptable excuse to not sit and watch TV, or go to the mall for no good reason maybe spending money I don't have on things I don't need. I deserve to have private down time, sans parents. Then I can meet their needs, tomorrow.