Lucian's E and Q just don't go off at times

Am I doing something wrong? It's not like I'm silenced or anything, I look at my abilities, they're all available, and yet they just don't go off. Especially the E, to dash away from danger, that is MOST annoying, to rely on almost half of my arsenal, feels so unfair. Are there any special circumstances in which the E should or should not go off? The ability itself doesn't say much.