Yup, Trek. I watch Trek series in order for a single series, but not necessarily in franchise order. IOW, I start at the first episode, and watch every one til I get to the end, and I don't mix others in while I'm watching. I do make an exception for new Trek, and I'll mix those in, but they're kind of segregated in my head. The golden years of Trek ended with Enterprise. Not to say there hasn't been fantastic new Trek, but it's just /different/, and the seasons are so short, you can't watch so much it scrambles the different "worlds",
I watch that way for two reasons. It makes me watch episodes I'm not that excited about, and they all have something to offer, even if they aren't great. It also makes the good ones last longer, when there's Bs & Cs to flesh it all out. I also want to get lost in a single world. Each series has it's own "groove", and jumping around makes it harder to get in that groove.
I guess there's three reasons. I also don't want to get in the habit of watching the "greatest hits". When you do that, you can tend to overlook good episodes that don't make the A tier. It's like music, and especially digital music. It's easy to just play the tracks you want to hear. Back in the day, you had to listen to a whole vinyl side unless you wanted the huge hassle of dropping a needle in the middle, and even with cds, it's kind of a PITA to listen with a remote in-hand to skip around. Digital makes it too easy to hear the premium tracks, and you can overlook good stuff that doesn't come immediately to mind.
Back to tv... I don't watch a ton of video, and I keep fairly sizeable breaks between viewing sessions, so the old shows stay fresh. I don't mindlessly watch anything. When I commit to watching, I want to really watch, and I want to get the most enjoyment out of it that I can.