I had to string up an exhaust on my Clio. The bracket snapped so had to tie some bright blue string around the thing and lash it the boot catch. Stayed like that for about 3 weeks before I got it sorted. Still - got my first aftermarket 3" twin Pipercross exhaust out of it sounded like a proper chav chariot then!
On the Celica, if you discount the fact a raked a socket driver down my rear quarter scratching the paint when fitting a new boot strut, the worst I've done is hack my wheel arch liner to death whilst trying to fit an Injen CAI to my last T-Sport. I wasn't anticipating the tight angles I'd encounter and in typical Gaz fashion went at all very ill-prepared. That poor arch liner got raped with a rusty saw knife looking thing and a pair of reasonably blunt snips. It was pure carnage and definitely my stand out "f**k it, that'll do" moment.
Oh... and as for the paint - nothing a little touch up pen didn't *uh hem* fix.
I try not to dabble tbh - I'm not that clued up really and most things rarely go well when I use my hands, I'm surprised I've stayed married so long