This one irritates me as well. There's nothing wrong with mentioning a negative point about a bass, especially if it's totally subjective. And, to be fair (probably another phrase that irritates, haha), maybe you're selling it to obtain a dream bass or something you think is better, but then don't praise it to high heaven because then I wonder if you're lying to sell the bass or covering something up (like it neck-dives so much the headstock hits the ground).Best bass I've ever played, but selling it to fund another bass.
We're a bunch of cranky old men (and women!), are we not? (Even the young'uns!)