As a hobbyist, rather than a trained bike mechanic, I try a lot of things that are obviously crap in hindsight…
I’m sure I’m not the only one so maybe this thread can serve as confessional.
The first build of my Surly Karate Monkey used square taper cranks. With so many crank interfaces I thought I’d play is simple with square taper - and square taper is square taper, right? Wrong! Campy cranks (ISO square taper) only just fit on to a Shimano bottom bracket (JIS square taper). You could ride it but couldn’t trust it.
The mad hippy helped me out with some cranks so problem now fixed.
I had some garish yellow Tioga riser bars that I thought would look a lot better black.
A couple of coats of rattle-can later they were done - but the bar diameter has increased so brake levers and lock-on grips couldn’t fit.
We wanted to convert a mate’s flatbar hybrid (Avanti Blade) to drops… but of course the diameter of drop bars is fatter that flat bars!
A six-pack later a lots of swearing they were on - but the bars got scratched up bad (thank god for bar tape).
That’s because you went against nature. 
Squeezing Nitto bullhorns into a road stem.
Not a good idea.
Trying to fit 27x1/4" tubes into 27x1" tyres… 
I Soon bought 700x28 tubes and all is good now.
Hoping the Sprite can shim I’m got with my risers and Cinelli stem works (it hasn’t moved yet)…
got a puncture at the trails on my bmx years ago, stuffed the tyre full of grass and dirt like i’d seen on bush mechanic and rode it from St Andrews back to Hursty station.
howd that work out for you
prolly better than riding a complete flat
well… it got me from A to B…
didnt do wonders for the rim when cornering.
Went through two tubes when i got a new rim, I didn’t fit any rim tape and inflated the tubes which keep bursting…can’t believe it took me two tubes to figure it out…
Did the same thing when I built up a new bmx early last year.
I broke a pair of bars on my mtb when I was a young lad and all I had was a pair of renthal motox bars which were too thin for the stem, so I did it up as tight as it would go and then drilled a hole through the stem and bars and put a bolt straight through the middle. It worked for about a month or so.
My friend did the same, kept getting flats, went to the bike shop to see what they said… oh how the laughed.
Trying way to hard one night to get a bike finished to go for a ride… tried to put the bottom bracket shells in the wrong side, thought the powder coater fucked the threads. :oops:
The truth comes out hahahaha.
Got my first puncture out on the road up the hill from Frankston (ie about as far away from home as I was going to go that day) when I first started riding. Changed the tire hopped on and couldn’t work out why it when down straight away. Tube no.2 goes in, same prob. No more tubes and its mid winter and raining. Walking back to Frankston when a friendly rider stops and gives me a third tube - after a chat he suggested I run my finger around the inside of the tube to check - sure enough a nail was still stuck in - doohh. 
I tried to replace a BB last week and had no pin spanner to tighten it up.
After snapping 2 2mm allen keys by using them as levers I gave up.
Bought the right tool and used it to turn the BB cup 1/4 of a turn.
There’s $30 well spent!
:evil:
Any good tool is $$ well spent!
First time I took off a chain I pushed the pin right though and out the other side. I tried for hours to get the pin back in with lots of swearing. In the end I bought a new chain. I now turn a bit, check the pin, turn a bit, check the pin. I hope to god I never do it again.
I’m quite fond of the old “That’s about tight enough, now to crank it just a little bit more for good measure” break 
Or, a recent favourite, “Hm, this crank puller is not threading on very easily. Time to apply a little brute force” strip
I’ve lost count of how many times I’ve walked out of my garage feeling like Homer Simpson…
The sad reality of why I missed that ride But i’ll be up again this Thurs.