The naïve Tailgate needs to be liked. It's hardly the most unique of flaws, but he has an unfortunate, childlike tendency towards extremes. Placed in a situation with Autobots who don't know him from Primon, this sanitation 'Bot will spin a tall tale the height of a Metrotitan in an attempt to impress his fellows before it all comes crashing down. And it ultimately will - while he's a 'Bot with a spark of gold, he's broadly unfocused, frequently distracted and easily led, and often gets impulsive, irrational obsessions. And his timekeeping sucks.
Easily his most distinctive mental issue is his occasional inability to tell the difference between a non-living Earth machine and sentient robotic life such as himself. While it's a mistake many other Cybertronians have made at first, typically they learn quickly and let it go. Not Tailgate. Once he gets it into his head, his compassion turns to rage against the "enslavers", and is quite vocal in his desire to "free" the machines of Earth.
That boy ain't right.
Sometimes, he acts as a scout—with strict orders not to break cover for any reason. In this, he is aided by a ridiculously powerful iron-cobalt magnet installed behind his bumper, which he can use to follow closely behind other vehicles and travel far into enemy territory using minimal fuel.
His alt-mode is a Pontiac Firebird Trans-Am.