A habit I've gotten into is if I scrub my beer glasses with dishwashing liquid, I boil them afterward to remove the soap/parafin film inevitably left by that stuff, and towel dry them to remove some of the calcium deposits from our very hard water. The primary reason I might use any soap when I wash them is if I use them for a beer that has highly oily grains, such as oatmeal, or any adjunct with oils (citrus peel). Oil and foam don't play well together, and the oils will stick to the glass. Nothing to be done for that. That's exactly the way "spot-free" and "Sparkling Clean" technologies work. If you have a brew that's got a lotta oily flavorings, you're going to have to compensate with something. That something will largely depend on who you ask, and some personal experimentation.
Now that I've seen the comment about dry-hopping, I'm a little concerned about my last batch that I dropped some Galaxy in trying to duplicate Kona Big Wave. But, it had a ton of wheat malt in it (American Pale class), so I may be worried about nothing. It's my first dry-hop batch, so it may turn into pig swill anyway.