Shagdac is right. You must understand why you hate the piece in the first place.
Personally I cannot say I hate any piece. My negative reactions to pieces tend to fall in these categories:
i. Dull. Certain pieces (personal taste of course) I find unbearably dull. For instance, most of Bartok’s Mikrokosmos. Being now at a position where I do not have to learn this sort of stuff, my heart sinks when I come across a student who actually loves the stuff.
ii. Mediocrity. Certain pieces (usually pop) are simply not up to standards (not personal opinion, I am afraid). Again my heart sinks when a student will not rest until s/he has learnt the “Titanic” theme.
iii. Overplayed pieces. Certain pieces are now definitely no-no. Fur Elise for instance.
Any of these negative emotions are justifiable grounds to refuse to learn a piece. Life is short and the piano repertory vast enough that one does not need to waste time on dull, mediocre and overplayed pieces.
There is a fourth kind of piece that generates some pretty strong negative emotions in myself, but this kind I always make a point of learning:
iv. Difficult (for me, at that time) pieces. Pieces that I look at the score, or sight read through and I immediately realise they will take forever to learn. Dismay, despair, discouragement and suicidal thoughts are not unknown to cross my mind when faced with one of these pieces. Yet, these are the pieces that are bound to teach me the most and to advance my piano skills the farthest. The only reason to avoid such a piece is if it also belongs to one of the three categories above. (Yes, believe me, there are plenty of pieces that besides being extremely challenging to play are also dull, mediocre and overplayed).
So, what is it that you dislike about this 3-voice invention? Is it just the difficulty? (It is difficult). Or even listening to it on a CD grates on you? If it is just the difficulty, go for it, because it will teach you much. Otherwise just choose another 3-voice invention that you like (to listen to – it will be equally or more difficult).
Also remember that Bach’s music is motif based. Part of the fun in learning it is in following the motif: How it gets inverted, transposed, turned backwards, augmented, developed, etc. I am always amazed how so many students just dive straightaway into Bach’s pieces without ever bothering to isolate the voices, and the motifs, and the several ways that he manipulates them.
Finally bear in mind that these pieces (and the 2 voice inventions) were originally meant as composition exercises first , and only second as technical exercises. Analysing how they are built is at least as important (if not more important) than practising them at the piano (in fact the analysis will guide and inform your practice of them). In short , do not approach them with a simplistic emotional attitude (like/dislike), but with intellectual curiosity. I cannot understand how anyone who approaches Bach with intellectual curiosity can ever dislike his pieces.
Finally you mention fingering. There are two main difficulties with fingering:
1. The fingering is awkward or uncomfortable. If so, change the fingering (sometimes it is not possible though)
2. The fingering is ideal, you do not want/need to change it and yet it seems almost impossible to memorise the fingering. It seems as if one cannot help but use the wrong fingering (this is quite commom with Bach). If this is the case, then you have to work in small sections ( and in the case of this invention, you must think separate voices, not separate hands) and repeat them endlessly making sure you are using the same fingers all the time until you simply cannot use the wrong fingering. Your fingers "just learned" the correct one.
I hope this helps.
Best wishes,
Bernhard.
Topic: Hating a New Piece