Hi, Deviless. There are some FUN music books out there that are also "technique" books. May I recommend "Alfred's Basic Piano Course Top Hits - Solo Book" (from Levels 1 - 6) which feature popular Broadway music. I completed the Levels 1 - 4 books under my previous teacher (along with my graded John Thompson, Bastien, Czerny and Alfred's Basic Learner's books) and my current teacher just "bought" me the Top Hits Level 5 book, so that my practice is not "boringly" confined to classical/exam pieces.
There's another WONDERFUL piano book series called "Upgrade" (by Pamela Wedgewood) with original pieces composed by Ms Wedgewood and meant as practice pieces before you start a higher grade. The music selection comprise of varied styles (jazz, classical, etc.) and each piece evokes a different mood ("brightness", suspense, jazzy, romantic, melancholy, western/cowboy, etc.) and is beautiful, melodious and FUN to play! And they're good for improving "techniques". Maybe your teacher will approve of this piano book series.
Personally, I love classical and movie music and have dozens of sheet music and music books which I bought on my own and practice the pieces I like privately, just for FUN (my teachers don't know I have these books

). I usually can't play these pieces well because they are technically beyond my "level" (but I like to collect them for the "future"). And I'm sure my teacher wouldn't approve of my tackling these music because I might neglect practice on my "lesson" pieces. But I'm gearing for exam next year, and must focus on what's important now which is to practice more on my scales and classical/exam pieces. I will be more worried if my teacher doesn't focus enough on preparing me for the exam and instead encourages me to play "fun" pieces!
Deviless, you wrote that you "sometimes got so bored and frustrated with the pieces". Well, I experience this too. But I think, usually when a teacher pushes one to practice on a boring/difficult piece, it's with good intention. If the piece is appropriate for the grade one is in, I think it's good to practice until one gets it OK. It always feels great when I've completed a difficult piece, and the teacher tells me, "Very good. See what continuous practice can do for you? Now you've gotten rid of this piece and we can move on." And I would go like, "Phew!" There were some pieces I ABSOLUTELY hated practicing on (two immediately come to mind: Beethoven's "Minuet in G" and Clementi's "Sonatina"). Technically, these are not very difficult pieces, but for some reason, it still took me weeks to minimize my mistakes and it got to the point where I really, really hated the music!! I was sulky whenever my (former) teacher said to me, "OK, you need more practice on this. Try to concentrate on this bar and this bar where you made the most errors on, and I hope you do better next week." Sometimes, it was my teacher who 'sulked': "Didn't practice enough, did you? This is an 'old' piece, isnt' it? I hope I don't have to ask you to repeat this piece again next week." Now, if a piece is particularly dry/difficult/boring, I try to concentrate more on it to get it out of the way, so that I don't have to "look at it" again (ever!).

Right now, I have a difficult piece to practice on i.e. Burgmuller's "The Young Shepherdess". It's in C major, but some bars are just so difficult to get right. I've to do tonic, 1st inversion and 2nd inversion (all in appergio) and in mixed order, from top/right hand side of the keyboard down to the left, and the chords for treble and bass clefs aren't the same!