Which exercise is suprisingly very fatiguing for you?

I'm not talking about lower-body exercises like barbell squats, RDLs, or split squats, or even some upper-body exercises like pull-ups or Pendlay rows. These are obviously fatiguing for most of the lifting population. Recently, I’ve realized that the seated overhead dumbbell press with no back support leaves me winded. I'm obviously still going to do it, but I am always surprised by how this exercise beats me up. I'm interested, though, if anyone else has a similar experience with other exercises. I am probably no anomaly in this regard.