some blocks have no transactions except for the generation transaction.
"Greedy" miners ignoring free transactions of whatever priority (space allowing, of course) that are pending really sucks. And they are also hurting themselves, they just may be too dumb to know it - by causing transaction verification to be slower, they may be turning off other potential users of bitcoin - some of those potential users may have invested allowing miners to receive higher prices for their coins.
Really short-sighted and tilting. Once the block reward is reduced, sure, but not now.