Well, I can say I like jazz, but more on the written side of things. For an example, I totally dig Bill Evans' Very Early the first time I heard it. But as the piece goes on, here comes the improvisational part, which is just something I can't appreciate. Maybe the notes are too complex for me to hear any kind of feeling inside it.
Another example by the same composer:
Waltz for Debby
I felt that the piece started to lose its charm at around 2:05 or so. It's just too, erm, complex (can't find a better word right now). Sure the harmonies are great, it's great music, I understand that. But I just can't seem to get what's so great about it. Anyone care to shed some light? Another thing, IMO it gets its charm back at 3:33 or so, since I can hold back on to the main melody again.
That being said, I like improvising. I can't do it properly, just memorizing some scales and the such and playing it out. It's fun :P
EDIT: After having some thought about my problem, I think it may just be that during the improvised parts, I just don't know what to listen! Should I listen to the bass? The piano? The drums? Or all at once? All those don't make much sense to me when the musician is improvising. Anyone can recommend some pieces with improvised part that aren't so steep (for lack of a better word, again)?