Why do doctors say that the gallbladder is an useless organ and wont have any effect if removed, but people are experiencing lots of problems after?

Not essential: Gallbladder is useful but not essential to live. There are digestive issues without it.

Not true: Most people never have problems after gallbladder removal. Any post laparoscopic surgery pain resolves after a few days. A minority of patients have colicky pain for a few weeks after gallbladder removal, but even this pain also resolves after a few weeks when the body adjusts. Gallbladder is not really a useless organ, but it is a vestigial organ, much like the appendix.