Beast Wars the beetle from the Tripredicus combiner. Friggin annoying.

 

Alts Grimlock and Meister, can't figure the arms out. Next would be rid Galvatron into all 10 modes.

 

TM2 Megatron...Beleive me, I finally read the instructions...

 

Uhhh...Movie Ironhide

 

G1, none that I remember
Beast Wars: maybe TM2 Megatron and Tigerhawk
Beast Machines: None
RID: Sideburn, the transformation to make Omega Prime
Armada: None
Energon: Mirage the first time, a mention to Starscream for the arms
Cybertron: None
Classics: From the ones I own, none.

ALTERNATORS.....here is the deal, most of them were relatively easy, however, the mazda mold and the mustang mold were the ones that gave me more troubles

Most difficult in my whole life......movie Ironhide, just transformed to robot once in my life

 

G1 Throttlebots

 

hmm, Movie Blackout without breaking the Automorph, Alt. silverstreak (never realized the legs always were that messed up-couldnt get them right) and Ultimate BB, as he is tough to go from car to robot, as the snaps were tough.

 

Here's a couple who have been a real pain for my Cybertronian Neural Processor:
1-BW II :Tripredacus
2-BW Neo: Big Convoy....a superb Transformers, but Good Lord... 
3-Alternator Grimlock: still paralysed into a hybrid aberration, part car, part robot. Never bother to re-transform it into one of its official modes.
4-Superlink Superion: oh boy. (sigh)

 

"Cybertron" Beast Wars Primal.

 

BW Neo Mach Kick was a pain in my ass

 

mp megs and alt. wheeljack and grimlock! alt. prime gives me his fair share of hassles too!

 

did anyone say "twintwist"? just wondering

 

Mammoth Prime. Frankly gave up trying to turn him into a mammoth. When Dark Mammoth Prime came out, I got it transformed. Don't know why I got that version and not the other. Haven't retried the original version again.

 

I still dont understand why people have a hard time with the Alternators Mustangs, but no one ever mentions Skids. The Mustangs are mildly annoying, but they can be figured out with just a bit of fiddling. Skids' arms are an exercise in futility. Maybe it's just because everyone hates Scions so much that they never try to go back to vehicle mode.

 

I had some difficult time turning Movie Leader Brawl to tank. There were some pieces that didn't want to go where they had to  

 

Alternator Prime. My only Alternator. Still fail to transform him correctly back to vehicle mode

 

Movie leader megatron, MP05, and Ultimate Bumblebee when I first transform them.

and i dont think I will ever transform my MP05 again...

 

Funny, I can always get the arms right on my Skids...but getting the chest aligned right is a real pain in the arse. Just way too many hinges...and there's always ONE that's in the wrong position that screws the whole thing up.

I also have trouble with Movie Leader Brawl in getting arms back in and getting the sides of the tank locked in. Most times I can almost get it..then the front bits spring back and all my hard work goes to pot.

 

I had the same problem until I noticed that the arms have to go in a very specific way...you have to push'em inside and then a little towards the roof of the car.

(I don't know if you understood, but I tried to explain in my best English  )

 

MP Megs by far. After fiddling with him for 3 hours everything else is just a kids toy.