Flattop

If you looked up "survivor's guilt" in the dictionary, you would probably see a picture of poor Flattop. This unlucky wretch has no escape from the tormenting memories of having seen his friends suffer and die all around him.... no escape, that is, except his own miserable death, which he is powerless to prevent. Try not to be near him, and definitely don't let him talk you into anything.

Fiction
Flattop persuaded his fellow Autobot Military Academy cadets Tailgate and Subsea to undergo a rite of passage in Cybertron's treacherous Underworld. Once there, they found it populated by violent, malformed mutants. Paralyzed by fear and guilt, Flattop was helpless to save Subsea from a grisly death, and he himself was soon incinerated by Smeltdown.

Flattop served under Flame at Babu Yar, fighting against Gideon's Decepticons. That battle became infamous due to the deployment of the horrific napalm-like chemical weapon Gideon's Glue, which rained out of the sky and simply dissolved most of the Autobots. One of the few survivors, Flattop accepted High Command's offer of a new body—but nothing could heal his psychological trauma, as he was from then on depressed, nervous, and prone to reflexively seeking cover as much as possible. His luck did not improve during his next mission, on Hydrus 5, where during a patrol he saw a strange greenish apparition. Interpreting this as the Shimmer—a mythical Autobot symbol of impending death—Flattop fainted from terror. In actuality the vision had been Springer's holographic attempt to invite Flattop to join the Wreckers, but Springer was so disgusted by Flattop's emotional reaction that he severed the connection and never thought to explain himself afterwards. Now with a double dose of psychological shock and fully convinced he was going to die at any second, Flattop's life was ruined and he was directed to Rung for psychiatric counseling. Rung attempted to dispel Flattop's fears in the Shimmer by insisting it was just a legend, and that his visions had been the result of lingering post-traumatic stress as well as perfectly normal optical glitches in a brand-new body. But Flattop never heard this, as at that moment an undetected microscopic remnant of Gideon's Glue, still oozing through his systems, penetrated his brain and killed him.