1. There are fewer episodes than American non-cable equivalents.
Sure, having around 12 episodes instead of 20+ is a bit frustrating when you really love a show. But consider what it means. Half the season can mean twice the budget for each episode (this is why big-budget cable shows like Game of Thrones and The Walking Dead can stay on the air). Even when a bigger budget doesn’t apply, it usually means the story is better. You are less likely to get filler episodes and meandering mid-season subplots.
2. Familiar faces.
What’s cool about BBC is that they tend to reuse actors even if it’s just as a guest appearance, especially where Doctor Who is concerned. For example, Merlin regulars Colin Morgan (Merlin), Angel Coulby (Guinevere), Anthony Head (Uther), John Hurt (Kilgarrah) have all appeared in separate episodes of Doctor Who. You will also see a number of BBC actors appear in movies. Sherlock’s Benedict Cumberpatch was the villain of Star Trek Into Darkness and Martin Freeman is Peter Jackson’s Bilbo Baggins in The Hobbit movies. It’s not only fun to see different sides of actors but you sound well-versed in pop culture when you can reference past work. Win win.
3. The United States will steal the idea anyway but it’ll be horrible.
Plenty of US shows have come courtesy of our friends across the pond. Being Human, Skins, The Office, Mistresses, Viva Laughlin! and Eleventh Hour all started as British series. Most don’t sound too familiar right? That’s because they weren’t good. Watch the originals. (http://en.wikipedia.org/wiki/List_of_American_television_series_based_on_British_television_series)
4. British humour.
Sarcasm, innuendo, satire, dark humor…it can take a while for some viewers to get used to it. There’s also a tendency for smart characters to do silly things. American shows, comedies in particular, tend to be over the top with stupid characters doing stupid things. The new FOX show Brooklyn Nine-nine comes to mind; I can’t even look at the promos without rolling eyes. Something can be said of some subtlety every once and a while.
5. The culture.
We live in a big world that is continually made smaller by technology. Learning a bit about British culture and history through their TV isn’t a bad thing. It makes you a bit more cultured and well-rounded and you get to listen to fun accents, which is always great.