I really dislike the casting of the same actors in different roles, without explaining it properly, or stretching it really, really beyond belief. Adam Soong for instance... I don't really like that there are now 4 ancestors of Data that look EXACTLY like each other...
There are three generations of my family who all look very similar/nearly alike. I look like my father (and have been mistaken for him several times due to early greying hair), who looked like his father who also looked like his.
I'm very sorry for the poor casting choices in my family! We'll have the showrunner fired and I shall be recast as soon as my contract runs out.