Worst is people that name the kids the SAME NAME but with a different spelling, a la:Stephen and Steven (I've seen this one in real life) Lily & Lillie Katherine & Catherineetc.
Oh! Totally forgot that I know a Dallen and Dalen. Their mom thought people would know the pronunciation was supposed to be Dal-en (al, like Albert)and Day-len. Yeah, no... everyone said them exactly the same. Suffice it to say that Dallen goes by his middle name Ben (Benjamin).
Also, I really dislike names that are essentially the same but one letter is changed. There were twin boys I took care of a few years ago named Tailor and Tialor. They were supposed to sound like Taylor and Tyler. Even that sucks, but would have been lightyears better.