If the walls you are talking about are common property, then yes. If they aren't, then no. They will be common property if they are either adjoining another apartment or are essential to the integrity of the lot (ie, prevent flooding from bathroom). But only your strata plan can tell you.
Re your regrets, go to your window, look at your view (if you have one) or at least your location. Think about the added security you get from being in a strata block, then ask yourself how much it would cost to have a free-standing home that offered this and all the other benefits of strata living. The trade-off of having to observe a few common-sense rules is well worth it. Just because there are some negatives to strata living doesn't mean all strata living is bad.
Feel better?