Neither Good nor Bad
It's really easy to categorize each tarot card as either "bad" or "good." That is, a good card is one you are happy to get in a reading; a bad card is one you would prefer not to see.
Even Eden Gray, the mother of the concept of the Fool's Journey and much of our modern exoteric philosophy of tarot, referred to specific cards as "good" and "bad."
It's true that most of us would rather see the Star than the Ten of Swords in our reading. But it is important to temper our enthusiasm for pretty images and our repulsion from scary images with our understanding that each card is important and necessary and that each card brings information.
So much of how we interpret cards in a reading should depend on the question. In tarot classes I often ask everyone to ask the same question of tarot and pull one card. New students often have a difficult time interpreting the card in the context of the question.
When we use a tarot spread we interpret the cards not only in the context of the focus, question or position but also in the context of the surrounding cards.
So how can context affect our interpretations? Let's use the example of the two cards mentioned earlier, the Star and the Ten of Swords.
Typically, the Star is about hope, healing, enlightenment and fulfillment. But if the question is about a potential love relationship the Star might indicate a great sexual connection. If the question is about someone's personality the Star may indicate a "diva" quality - a person who wants immediate gratification.
The Ten of Swords usually refers to a difficult situation. But it can also be a positive card in that it can indicate the end of a difficult period. It can also indicate that one has found the strength to acknowledge and leave a difficult situation.
Some tarot cards are prettier than others. Some inherently carry a more hopeful message. But it is the nature of the question and the surrounding cards that will determine the nature of the message each card delivers.