Despite the advantages of being able to work without gloves, or with very light gloves, I would definitely recommend having a heavyweight pair for those occasions when you suspect the girls might be less forgiving than usual. The knack, of course, is to avoid bothering them at times when you know it will wind them up... but perfect timing isn't always possible.
Today reminded me of doing this poll a few weeks ago. I don't normally wear gloves because I'm blessed with fairly forgiving bees and like to be able to feel what I'm doing and avoid clumsiness with frames etc. However, today I wore my leather gloves because I knew the girls would be cross, and boy am I glad.
It's a classic example of how calm bees can get defensive under certain cirumstances. They're making queen cells, are already more advanced than I expected at this time of year, and I wanted to move some of them into a new brood box. That particular colony has a huge brood area and is brimming with bees. A really strong colony can make gentle bees a lot more "forthright"... And these had put honey into brace comb, and reacted angrily when I had to break some of it, something I'd normally avoid if at all possible. They really clung to me, and had a right go at stinging my gloves. I was very grateful for wearing them - the prospect of maybe dropping a frame or, much worse, a box, under a barrage of stings is too bad to think of
Within an hour they had all settled down, disappeared into their respective boxes, and apparently forgiven me. However, I will be putting the gloves through a hot wash before I use them again.... they must reek of angry bee!