I can't decide between "one word 'comments'" and "please look at my gallery". If I have nothing to say I better not say anything. I always like my comments to be thoughtful, and not mean at all... Constructive criticism all the way (I hate destructive criticism too).
The "look at my gallery" ones bother me more, one-worders I can put up with but at the same time not worth responding to but I'm the same as you with giving comments - usually if I can't think of more than, around 7 words or so, I don't bother saying anything...it has to be unique to that peice, as anyone can say things like "great colours" on practically anything (that isn't black and white )
Hmm, I guess critiques from strangers can be acceptable, especially if you see their gallery and it's really good and they know what they're talking about but it can be hard to take someoen seriously when their gallery is either really bad or even non-existant