I think in comparison to other fans, our extremes of praise followed by disappointment and criticism then back to praise again is much more balanced, and it doesn't linger long. Just pop on the mackem board after they've lost a couple on the bounce or went a handful of games without a win and you'll see the vitriol aimed towards their players, manager, and owners is shameful in comparison. They even turn on each other and occasionally blame their own 'fans' for how poorly their team is playing or how bad their club is being ran. They'll win their next game and they're back to being the greatest team in the division and best fans in the land again.
Call it passion, or delusion, but they're literally in another league compared to Boro fans when it comes to this kind of thing.
So yes, the criticism-praise-criticism thing runs across all fans and all teams. We're no different, but by some margin we're certainly not the worst at it.