It only becomes a visible problem in harbours (or otherwise in shallow waters).
It looks like a tidal wave in the sense that it's a lot of water moving in a given direction. The mechanism causing it is not the same at all, so the name tidal wave is misleading.
As an example a friend of mine was on a boat during the massive 2004 tsunami, but since he was a few miles off the coast where the water was deep he didn't even notice the tsunami sweeping under his boat. Once it hit land it did massive damage.
It looks like a tidal wave in the sense that it's a lot of water moving in a given direction. The mechanism causing it is not the same at all, so the name tidal wave is misleading.