I for one hate soldering 
Even with helping hands, wires don’t stay together. There is always too much or too little solder. Even with ventilation, the flux and rosin smoke gives me a headache haha
Aligning enclosure and deck holes is also PIA.
On the other hand, I really enjoy the mechanical aspects. Like aligning pulleys, motor mounts etc etc
I wish I had a friend who enjoyed what I don’t like and vice versa. Would be perfect lol
Stuffing wires places. I have the habit of leaving wires a bit long for “servicing” and build changes. Really just ends up being annoying when I try to close the lid.
Leaving my dog in the house while I’m in the garage 
analysis paralysis - i overthink everything.
All the time it takes. I estimate a couple hours for part of a build or servicing. It ends up taking at least four or more hours everytime.
When you get new parts for a build but you can’t make anything because you dont have all of the parts so they just sit on your desk… and you just think abiut how fun it is going to be to actually ride it… 
Soon, very soon…
My income.
Batteries. I’m scared of batteries. Oh and that small bit from china you forgot to order. Oh and my 11 year old who routinely steals my tools for his scooters and rc cars.
And my wife finding out the reality of what things cost.
Explaining to my gf why there’s no money for groceries after a part buying binge…
My cat gives me this everytime I’m outside at my workbench
Something like that for me too. I buy everything online and mostly from China’s taobao, which will require me to consolidate shipping for different parts, sometimes parcels go missing… I’m still waiting for a large parcel that I bought on 11.11…
I feel you man. Just got word today that idea’s cnc mill broke before he could finish my motor mount.
Hate to rub it in but 
But dont worry. I am waiting on a anti spark switch too. Can do shit without it haha
when you buy new parts, get super keen for it, it comes, and it doesn’t fucking fit
even worse, you buy what you think are 2 compatible parts but they don’t fit and you have to buy the same shit twice.
Waiting for parts to be delivered!! 
drilling into a deck, knowing that it will never be “perfect”
Crimping JST connectors when you don’t have a crimper
And spot welding because I suck at it and sometimes the contact is not good enough or I short the probes and it goes boom
I take my time I don’t mind taking along time but I hate having to fix something repeatedly, that’s my biggest urk but sometimes it just has to be done till you find a solution.
looking at the bank acount