(FYI-- "Up my alley", not "up my street") "then again" is similar to "on the other hand". It means you said one thing, but now you are going to say something that *could* be contradictory. Bad: "I like candy, but then again, I hate all sweets." This is completely contradictory and therefore would not work. Bad: "I like candy, but then again, I like Snickers." This is completely consistent and therefore would not work. Good: "I like candy, but then again I always seem to get a rash when I eat it." This person obviously likes the taste of candy, but their body does not like to process it. There is a contradiction, but it is not complete. Good: "I love my family, but then again, we fight every time we are together." This person loves their family, but they understand that an outsider looking in would not think they love each other because of the fighting. It looks like a contradiction, but it is not a real complete contradiction. In your examples I like: 1 (documentaries are compatible with your job/personality, but you don't watch them, so one wonders if they really are compatible), 3 (good swimmer, yes, but maybe your skills have atrophied) 4 (family is better, but then friends are also essential, so perhaps the ranking is not so obvious). In each of these there is a statement followed by something that makes you doubt the first statement. Less successful: 2 (Sounds like you don't like English, but you are forced to study it. These 2 thoughts are consistent. Just say, "English is not my cup of tea, but I must study it") and 5 (Again, completely consistent. You love dance, and you love watching your daughter dance!)