for me it would be forehand or backhand topspin; I usually don't play like that, I only use a bit topspin if my opponent gives my a slice to answer that stroke offensively
(or special strokes like backhand overhead... I hate being at the net and getting high balls or lobs to my backhand side)
My volleys. I mean, I can put away high ones and stuff, but if they're hit low or something, forget about it. I cannot tell you how many volleys I stone right into the net lmao. And surprisingly, my forehand ones are worse than my backhand ones, I think lol
I am horrible at putting away volley's with no pace on that aren't high enough to swing volley or overhead, especially on my backhand. My ad court second serve can be shakey, and my forehand can be horrible if I'm not timing the ball well.
~just an update. after long hours on the practice court, these problems are not issues for me anymore.~