If it is direct, it means you are sacrificing others. It is not a good thing as said above. You can find happiness and be selfish in various ways that will not directly harm others.
In Atlas Shrugged, refusal to remain a part of the system is just this (John Galt, the gulch) - trying to find one's happiness, without directly causing damage to others.
The whole society may be less happy due to the refusal of a few to sacrifice, but it is an indirect damage, an indirect cost. The alternative would be their sacrifice - a direct damage.
IMHO no man is entitled to happiness at the direct expanse of others.
So many example - I don't know if there is a generic answer!
But let's take them one by one.
Physical coercion is always wrong - it has a direct cost on others.
Layoffs are fine - no one has a right to work.
Hostile takeover - ownership right are respected so that's ok.
Fracking is an edge case - a negative externality if people already lived in a place and expected no such new industry would show up - so in that case, at a direct cost - and it becomes a bad thing.
If however similar or identical industries were already in place, yet people decided to move in, it's freedom - and it's fine.
Medical testing - I guess that would depend on what you mean by unethical. I'm sorry I can't answer for that one, expect by default a "direct cost" if you mean people entered medical testing while not being told the whole truth if laws requiring the whole truth to be disclosed exist, or in their absence if they were lied to. That's because it's just like cheating in a contract.
I hope this helps.
+1'ing you anyway since it's an interesting questioning about limit cases (and flipping the bird to the downvoters)
