While we may usually think of emotional moves as those made suddenly due to fear, anger, or impatience, the phenomenon is actually broader than that. There are moves you make because of emotion, but there are also moves you avoid because of emotional considerations. One of the main reasons I lost Annotated Game #2, an English Opening, was because as White I refused to consider playing the move e4 at a critical moment. I felt this would be an "un-English" move and in my own, somewhat warped view of my playing style, I believed that I was a flank opening player rather than a classical opening one. Somehow e4 "felt wrong" not based on an objective evaluation of the board position, but on my own feelings about ever playing the move.
This is all rather silly, but unfortunately is an example of what can be a typical attitude at the Class level. It is common for people to have strong preferences, whether for particular opening setups or for typical middlegame plans. When our preferences become emotional, however, this can often cross the line into a refusal to consider other options, including the best ones on the board. Simple things like always fianchettoing your bishops, or never fianchettoing your bishops, can be examples of this. Another common emotional decision is to always go for a middlegame plan of an attack on the opponent's king, because of the excitement factor or because you are naturally aggressive, rather than the attack being based on hard strategic and tactical calculation. (Silman called this "the curse of the mindless king hunter" in The Amateur's Mind.)
I was an example of the other side of the emotional coin, never going for an attack unless specifically provoked into counterattacking and usually playing passive, "positional" chess. Lack of tactical and attacking skills certainly played a role, but I think fear of risking an attack and having it blow up in your face was also a large part of it. At some point, though, I started accumulating greater exposure both to specific attacking ideas and also to the key notion that as a player, you must do what the position "tells you" to do - if it says attack, do it! In that respect, review of well-annotated master-level games is an excellent way of making your chess more objective, as it allows you to see what works and what doesn't in specific situations.
This is not to say that your feelings on a particular day can't legitimately influence your decision-making process. Some days we are more energetic than others, or simply feel like playing a certain opening over another. This is both normal and practical. We also face tournament situations where we may have the desire to either conserve our energies for later rounds, or conversely to make a strong, aggressive push for a prize. There's a difference between these kinds of high-level considerations, however, and the silly, unobjective feelings that can derail our thinking process and lose us games.