Why do people caution against becoming a parent

Im in my early 20s, been married a couple of years. Everyone around me has discouraged me from having children. Parents, grandparents, coworkers, friends, etc. I understand kids take up a lot of your time and energy but what makes it so hard/miserable.

Im genuinely asking because I want to know, not as a smartass thats like “parenting isn’t hard”

Parents please let me know why people are saying this