Past tense vs present perfect tense
Solution 1:
The Present Perfect is a tense that connects the past with the present. We use it when the time of an action is not specified/important AND when there is an immediate connection with the present. In the first statement, the important fact is not when you made the appointment but the result of that action, that NOW you have an appointment.
In the second statement, you are talking about something that is a part of your life experience, which is the metaphorical bag we all carry with us in the present.