Fiat UNO turbo clutch cable,ridiculous design,the two bolts to undo the PULLEY are under the steering strengthening bar,amongst other amazing bits of design wank.
In fact,pretty much any job on one of those,although there's only about 50 left now.
Cool car though.
I'd also say any job on a r5gtt,all those pipes!!!
More modern cars,Renault Clio's ridiculous bracket on the top of the engine that wears the loom out and causes an injector to fail,you then get approx 2mm of wire to solder a bit of cable on,or pay Renault twice the cars value to get a new loom.
Sport Ka alternators,have to pretty much take the front end off to get access.
Had a boy tell me he could do one in 1/2hr,off you go,4 hrs later he gave up.