Frankly, the only part I dread is being interupted... I get on a roll and then it's one thing after another at times...
Sure, there're parts I like less than others, but al in all, it's all part and parcel of the "fun & relaxation" of building a model... Many times, the more ate-up a kit is, the more I like building it (That P-82 comes to mind, there)
But as with anything else, there ARE shortcuts and little things one can do to at least, if not eliminate, make them less of an impact on the entire process.. Masking, seam-filling, frame-masking, airbrush-cleaning (my solution to that is use it as little as possible, especially whenever there's a rattle-can color around).
Seam-filling, while it can't be avoided, can at least made less painful by using thinned fillers, i.e. putties that're easily thinned with liquids that don't attack the styrene (Testor's White and rubbing-alcohol, for instance), using shims and strip or sprue to fill the larger gaps, rather than things that require more than a few swipes of the sanding-films, and always wet-sanding (easy sludge removal, far fewer sand-scratches, and the films/paper cut better, faster, and clog less)...
Vinyl track issues, like them not taking paint well, can oftentimes be solved (or greatly diminished at least) by using a combination of sanding and dull-coating, and flexing them as little as possible by painting after installation, and adding "mud" and skirt-armor... Re-enforcing their glue-joints with sewing thread can solve fit issues if you have to remove a link or two to achieve a better fit (along with moving the idler-wheel forward or backwards, which, coincidentaly, is how the "big boys" do it)...
"Sagging" them with thread tie-downs around the axles of the correct roadwheels also helps eliminate the tediousness of indy and link-and-length AM- tracks, allowing the kit tracks to be used too (unless you need a specific track that's not included in the kit to model a specific mark or variant)..
At any rate, there's never been a kit that beat me... Although I've had to beat a few into submission... 