Players hit lobs too short, giving opponents easy smashes. The fix: depth. A deep lob becomes an attacking shot, not a defensive one. Don't worry about hitting the back wall perfectly while you're learning.
Hey Tom, what's the mistake you see most commonly with people playing the lob? It's actually not realizing how deep they should play that lob and playing it too short. So many times players will try and play the lob and they'll play it too short because they're trying to get the ball in and they're going to lose the point anyway. If you hit a short lob and they have an easy smash, you're going to lose the point. So hit the lob with depth, don't worry about hitting the glass, particularly as you're learning, but if you can get a good depth lob, that is going to be an attacking shot for you.