Go to fix something simple and make it worse requiring you to stitch wires from socket to socket

Snap a leg bolt by tightening too much

Drop a ball on your bare foot

Pull a fuse and forget to put it back in

Put an eprom in backwards

Replace flashers by mistake with 555 bulbs

Level machine by crawling underneath and lifting up with your back to adjust leg levelers

Snap a post stud by overtightening

Part out a game

Break a plastic while installing a protector for it

Forget to strap a game down and it slides forward in your SUV/truck bed

Buy a bunch of new parts for a game and never use them

Put a screw thread the playfield from underneath when doing a playfield swap, bonus if it's in an area right by the flippers

Adjust a flipper and instead of testing it by hand just flip and cause flipper drag butterfly on the playfield

Not know how many games you own or where they all are

Own multiples singly over the years because you have better memories of it than you do and realize you hate it when you rebuy it

Buy project games to make 2 or 3 into one really nice one

Buy a game just get to a better backglass for your keeper

Deal with tire kickers/low ballers when selling a game

Forget what parts you have and where they are until you order replacements

Let a playfield swap languish for years

Well, you just have to crawl underneath the machines on either side to do this. I have a pinball cart but it's just faster to go under manually.

I did find a better way to do it: Send my girlfriend's son underneath instead. That one is MUCH easier on my back.

Bring an EM back from non-working

Bring another EM to non-working by adjusting/cleaning every switch and taking a mostly working machine and making it non-working

Have a great game going on a WPC game and get a game reset as you were about to beat the high score

Pick up a game in an open bed truck and not thinking you need a tarp as it's nice out and having a freak rainstorm happen on the way home. Drive fast to avoid the raindrops

Move a game or large item (backglass/playfield) on public transit/plane

Get a game offered for free you don't want/take and kicking yourself later when demand rises for it

Thinking you're a good player and determining from your first tournament as you come in at the bottom that you aren't

Thinking your tilts are tight until you play in that tournament/or hosting a tournament and watching great players walk your "tight tilt" games all over the floor as they beat all your grand champions on their first balls

Dealing with tournament cheats or just whiny behavior