Not really. I use to get mad when it went below 2, but lately I've just stopped. I started to actually go for objectives and just have fun. I don't mind going negative in a game if I get 4 flag captures. I'll die for the flag; it's up to my team to get the kills.
K/D or even Ka/D isn't the be all end all anyway. I care more about my teammates' than my own though. Even though it's not a true indicator of skill in every situation, it's at least a guideline so you can see how they play and how they'll fare.
To make unfair generalizations, I figure if someone is over 2 (like me </stealth brag>) then they probably aren't gonna do much in the way of objectives. Whenever I play Oddball, CTF, etc., the higher K/D randoms on my team generally don't go for the ball or the flag. They may aid in the assault for said objects, but they rarely pick them up.
If someone is in the barely positive range, I figure they probably go for objectives, throwing themselves mercilessly at the enemy until the goal is achieved. That's not a bad thing, either. They play to win, not to have the gaudy stats.
If someone is 0.5 or lower, I tell them to return the game to Gamestop so they can get Call of Duty.
The last one was a joke, obviously, and those scenarios don't happen in every instance. But they are merely my observations having played this game a while. --- Private LUE is better than public LUE in the same way a 15-car collision is better than a 16-car collision. -CJayC
I used to care about my K/D in Halo 3 and Reach, but not so much anymore. As long as it is above 1, then I'm okay with whatever it is. I care somewhat about my K/D in Slayer, but not so much in Objective, since it doesn't really matter what your K/D is in objective, but it does to an extent in Slayer.