In any game, you'll find that there's some particular strategy which is highly effective, highly annoying, and super-cheap.
In Total Annihilation, this tactic is the Flash rush.
Some, if not all, OTA (Original Total Annihilation) online gaming societies ban people for Flash rushing. (Not being an online gameplayer, I only know this by reputation.)
Note: The Flash is a unit in TA which is widely considered "overpowered" because of its strong combination of speed, game-slowing firepower (some people disable the Flash [and its robotic counterpart, the Peewee, which is only a little bit less bad] not because of its use in Flash rushing, but because its gun slows the game down so much when fired en masse), and sheer incredibly low cost. What makes things even worse is that the Flash's counterpart in the game's second faction is pathetically weak, especially by comparison, meaning that only master players intimately familiar with the game and with truly insane micromanagement skills can defeat even a typical Flash rush spam attack if playing that side-and even those won't always save someone on a map as small as the one shown above. (The game shown above is actually a game by an experienced TA player against the game's nearly helpless and comically inept AI.)