I have been feeling the exact same way that you describe, and have felt like it for a while. It is like you say, when i first started trials the main thing that kept me going was the great feeling of achievement, but now thats not there anymore. Like the other week i was riding a stack of pallets in my garden, trying to pull a big bunnyhop to front wheel up them. I eventually got it in the end, but when i did i didn't get a great feeling, nor a sense of achievement, just an "i'll try doing it higher". And all this has made trials feel pretty stale, and made me feel like i either needed a change, or start a new sport a long side it. Even if it is a move or line i have been trying to nail for ages, then i do it, it's just an "that was good", and a second later it's forgotten and back to getting angry trying a new line. So in the end i started bmxing, as well as trials. And needless to say it has helped a lot. It all feels a lot more fresh now, and i have found my self just enjoying it more, wether that be going for a quick blast around the block (brakeless of course ), or going to a spot and getting some moves down. It hasn't got the feeling of achievement to the same extent as when i first started trials had, but all the same it's still there. Also when you do get back on the trials bike after having a week or two off riding it, it doesn't feel like the same old stuff. You get on and feel a lot more fresh with it all, as well as having a new frame of mind from combining the two disciplines together. Soooo, i'm with poopipe on this get your self a bmx, and let the inspiration begin. If you do, make sure it's brakeless