There's a good reason why I never watch an american show in prime-time: to support canon..., the good kind that is. Let me break it down for you.
As you know, ratings play an important role in keeping a show on the air. Obviously, we didn't make shows like Criminal Minds, 30Rock or South Park. So, watching these shows on a Canadian network wouldn't have any influence on how they do on their native channel in the States. Furthermore, thanks to a little something called Simultaneous Substitution, all ratings and revenue for americian shows that air on a broadcast network goes to the Canadian television network that aired it.
To drive the point home, thanks to the development of on-demand services, we can watch americian shows anytime, anywhere. So it makes more sense that, if there's a Canadian show you like watching and want to make sure it stays on the air, you watch it as soon as it comes on. Here, your viewership will count and it'll let the network know you want more. Meanwhile, you save the american shows for a rainy day and watch them at your own leisure. Don't blame yourself if they end up getting canned, that's between americian networks and their viewers.
OK, so what about two Canadian shows that you like? For example, should I watch Citytv's Seed or Slice's Big Brother Canada? Ignoring the fact Big Brother Canada is the only original show on Slice worth watching, what you gotta do is try to predict what show people would want to watch more. Seed is a fledgeling comedy that's not very popular; Big Brother Canada is a Canadian version of one of the biggest reality franchises in the world. Obviously, more people will watch BBCAN and, chances are, it will be renewed for a new season. Meanwhile, if I don't watch Seed, it will not get enough viewers and will probably be cancelled.
It's a no-brainer: I'll watch Seed now, and watch BBCAN later. In doing so, I'm preventing the less popular show on the air from getting canned before it reaches it's full potential.
And there you have it. If you want to keep shows like Lost Girl on the air, this is the way to do it. Of course, you're free to watch americian shows at anytime. Just remember, what you do for those shows, affects our homegrown content.