Probably good that we lost them. Judging by photos [1] of some of the rare cases of humans who were born with tails human tails wouldn't be aesthetically pleasing. Although perhaps human tails that are the result of something going awry might not be a good indicator of what human tails would be like if we had kept them.
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263034/