>>tonmoy+(OP)
There's really one thing missing from the guidelines IMO - "don't downvote for disagreement, downvote for offtopic/flamebait/inappropriate comment".
Well, this should be obvious, but it sadly isn't...
>>Pannon+Ch
A simple up/down vote isn't enough to convey on all the options. Most people take to be an agree/disagree button rather than good quality/bad quality button -- and I think that's a valid interpretation given the limited options.