I would agree. Often, we pop in for a water or soda on the way into/out of the hotel. Don't tip then. However, when the attendant spends 30 minutes talking to us about where we might want to go the next day and takes our plates without even asking, or bringing extra napkins, etc.. we do tip.

Last week a lady came into the lounge and asked the Concierge to make her a breakfast to go. She just stood there while the attendant toasted and buttered her bread, gathered eggs and sausage and fruit. Got coffee to go, plates, napkins, etc.. and then put it all in a bag. I have NO idea why she couldn't do this herself, but she did not tip. I thought it was above and beyond what the staff needed to do, but she did it with a smile.