Why shouldn’t we be content?

So I have been curious how being content falls on the spectrum of creating impossible goals. I remember when I was a little girl I had traveled to India and remember seeing homeless people. I was surprised to see them smiling and happy which I do understand now that you can be happy rich or poor. During a bus ride I remember I was really hot and was upset that there was no AC. But my dad said something that I can never forget. He said look at the poor people and see how content they are and despite them not having any comforts they seem content. Sometimes I look at my mom and feel she can lead a bigger life but she says she is content. Why shouldn’t we be content?