I don't think you shoudl be harsh with them..but I don't think you should be dainty with them either.
IMO it is like with children and being super quiet around them while they sleep...you shouldn't do that. The pickier you are with the fish the more stress prone you are going to make them.
Just scoop them up in a net, but make sure that the neat is wet before you touch them with it (dry nets are rather..prickly).
If you don't chase them around and around you aren't going to stress them. Best way is to come up underneath them...most never see it coming.
I do have a few though, that I have to corner with the glass...I get them to go deep into the net by simply tapping lightly in front of them..that makes them back up enough that I can finished scooping them out.