Stupidity: There's no reason for the Foot Clan to confront the Turtles at TGRI and show them that they are in possession of the last canister of ooze. They already have what they came for and nearly lost it by battling the Turtles. Even if they wanted to kill two birds with one stone and see if they could defeat the Turtles while they were there, they still could have sent one of the soldiers back to headquarters with the ooze before revealing themselves and not risk losing it in the fight.
Stupidity: The Good Boys learned about consent in assembly and knew about making a citizen's arrest, using the internet to find where the drone is sold, how to treat a dislocated shoulder, etc. but did not know that they shouldn't give out their address on the internet and invite a stranger into the house?
Stupidity: When seeing that the bridge is out, JLC could've easily climbed out of the sunroof and hop off the back of the limo and onto the pavement, suffering a few cuts and bruises at the most. I know that it would've been anticlimactic, but still.
Suggested correction: You're assuming that jumping off a runaway car is a simple task that anyone can do. She's scared out of her mind, and many people in a similar situation would probably be scared at the prospect of jumping off a moving car, even with the knowledge that they will be flying off the road shortly.
Stupidity: Luca's parents try to find him by splashing him with water. If they succeeded, Luca's cover would have been blown.
Stupidity: Jon and his sister drove some distance to Bolton to find Janet, but Jon couldn't remember the name of the mini-mart where Janet works. Jon's sister said, "Maybe we should visit every market in Bolton", to which Jon replied she was a genius and "that's what we'll do." Instead of finding a telephone directory and making calls (first starting with Janet Brown!), they drove within a 10-mile radius, stopping at every store (not just mini-marts), but still could not locate Janet. (01:19:55)
