Would you get mad if a person you were supposed to meet for special event abruptly changed plans?

Let’s say you were for example, supposed to meet with your girlfriend/boyfriend for a special occasion and you wanted to meet her at a certain time, cause you had to do some errands before the special ocassion.

And you had previously (a day before told her the time that you were going to pick her/him up and your plans as well) and then when that day comes you arrive a little later then the time you had set for both of you to meet, so you call her/him and tell them that have arrived and ask them if there ready or if they need more time and your girlfriend/boyfriend replies that they need more time,that there not ready and you tell them ok I will pick you up in half an hour or so,and you hang up. so after talking to her/him, around 15— 20 minutes after, your girlfriend/boyfriend texts you saying ’‘we should see eachother better at night’’. just like that!.

How would you take it? If So would you get mad and ignore them? especially knowing the fact that you already had plans to see this person at a certain time and had even talked to her/him, letting them know a day in advanced?