If you don't like the first few episodes of NCIS, you won't like NCIS.

If you don't like the first few episodes of Buffy the Vampire Slayer, you still might like Buffy because it doesn't really find it's voice until the last episode of season 1 (my opinion) or even up to the middle of season 2 (a fairly common opinion).

Some shows are all they are from the get go, others take time to evolve into what they wind up being, in which case you might like later episodes when you didn't care for earlier, or even vice versa sometimes.

And not all shows get "better". I thought the first season of the (original) L Word was a really good character driven drama. In season two it switched to a plot driven soap, and I grew increasingly frustrated with it until I quit watching it sometime later after a couple seasons of hoping it would go back to what it was the first season.