It seems though, that this question arises more frequently among those aikido-students that only just began training. Or is that just my experience?
I've been training for some time, and I've felt this occationally. Ususally it was when training with someone much more physically fit than I am, where I *thought* they were using a lot of upper body strength to throw me around, and not taking care with my body. This always has happened with training with people from other dojo fortunately. Whenever you go from one environment to another, there's the chance for mis-understandings. Generally, simply asking a partner to ramp it down a notch until I get warmed up is all it takes to correct the situation. Or having them ask me the same thing. I wouldn't make too big a deal out of it most of the time. Generally, even if that dojo as a whole likes less intensity, they often make up for it in other ways (more suwari waza, fewer breaks, less talking, something).