I'm upset at my partner for always changing plans.
What is it about your partner changing plans that bothers you so much?
My parents raised me to be punctual and so I feel we should strive to be more like that as a society.
I understand why you might be frustrated for your partner wanting to change plans, but you shouldn't get mad at them. Getting mad will just cause tension between you two and make the relationship difficult. Instead, try to talk to them so you can work out a solution.
I don't care about making the relationship easy. I want them to shape up and to be more commited.
Well if you want your partner to try and do better to be punctual then this is a conversation that may be worth the time. Just know that being punctual is much harder for some people than it is for others, so try to be understanding and just happy with the effort that you partner devotes.