I really like The 100. I find it deeply flawed from a science point of view, but I also realize a viewer has to go into this knowing they are going to cut corners in logic to tell the story.
With that aside, I do notice some odd things about some of the characters/actors from time to time. I suggest for this topic that fans post screen captures from episodes or at least give a brief explanation with episode title and if possible, the moment (i.e. time stamp) in the show for others to look up.

I will start this off with Dr. Abigail Griffin in season 2, after parts of the arc have landed. Specifically episode 3. Shortly after the Dr. gets electric lashings, she is in sick bay, getting her wounds tended to by her assistant. Councillor Marcus Kane is talking with her and she is sitting on a table. I noticed something I thought quite odd; the veins in her arms were popping out as if she were a professional weight lifter! I mean, she is soooooooo attractive and all, and super skinny, but those veins! Here is a screenshot: