As I've explained a thousand times in the game thread (although it doesn't seem to be getting through to some of the numbskulls around here), our team this year is playing like a veteran team - they virtually ignore the first half of games against lesser teams, just doing enough to lead slightly or keep the deficit from getting to double digits (what you call "playing like " when actually it's just saving their energy).
Then, some time in the second half (sometimes straight out of the gate, sometimes mid-3rd, sometimes end-of-3rd, sometimes mid-4th), they ratchet up the intensity, get some stops, make some easy baskets and hold on to win the game. That has been the formula against lesser teams all year. That is the way this team plays. Like it or not, that's what they've been doing and will continue to do. By contrast, against good teams they tend to play hard for all 48 minutes.
Remember, most of these guys are getting old, and are probably bored by much of the first 2/3s of the season. Let's face it, 82 games is a ridiculous grind (it should be 58 IMHO - play each team twice), and it is impossible to keep up the intensity the whole time. The NBA regular season is a marathon, not a sprint, and our guys are old enough and wise enough to treat it as such.