No, it is not a correct sentence.
The mistake is in the word <em />worse - you need to use the superlative (final) form of the adjective. Bad - worse - worst. So the correct answer would actually be:
Deciding to go to Barcelona was the worst decision I ever made.
The amount of air decreases.
Compromising your viewpoints and behavior is bad generally: it will in the end only lead to frustration and will be a hindrance in achieving one's goals.
There are many situations in which compromising the viewpoint is bad, and one of the is an interpersonal conflict: it might solve the problem in a short-term, but not in a long term.
Merchandise or possessions.
