Was romance in Star Trek well written?

There was a lot of coupling in Star Trek but was there a lot of romance and was it well written? Star Trek isn't exactly known for its romance and has in fact been criticized for its lack of believability or motivation within a relationship. But is this a fair criticism?

Char and Tristan take a look at all of Star Trek and try to cover as many couples as they can and figure out if they are well written, believable, as well as necessary.

What are some of your favorite Star Trek couples?