There was one species on all Trek series that I always thought looked laughable - in TOS and ENT it was practically all you ever saw, but there were lots of them in the other series also. I can't think of the name right now but I remember there being a running joke about how the Ferengi said their name.
I mean, there were no forehead ridges, no wrinkles to speak of, no antennae, no spots, the ears were very bland and boring, no nose ridges, only one mouth, very bland skin tones (although there were a few variations here, but each person only had a single tone, no color-mixing to speak of), only a few eye colors, nothing glowy - not to mention their hairstyles, very dull - and some of them didn't even have any hair at all! It's like the makeup department didn't even care. They didn't even give them much in the way of jewelry to wear, and whenever you saw one in civilian clothes they were almost always ridiculous-looking.