There are positive and negative consequences for being too loyal.

"Unless you can find some sort of loyalty, you cannot find unity and peace in your active living" - Josiah Royce.
Loyalty and being loyal seems like a good thing and something you need and its true, the state or quality of being loyal is faithfulness to commitments or obligation. However, besides being positive, it can also have some negative consequences. 

Loyalty is expressed as positive and brought into the world being a good thing, and it is. It is defined as honesty, love, respects, and devotion. Being a loyal person can have the ability to make people trust. Loyalty is found in brave, strong, and bold people and a truly loyal person is dependable in all problems. Loyalty can cause a person to be happy because it means someone cares and to make someone happy with who you are can make you happy and thats the ultimate prize. 

On the other hand, there is the negative effect of being loyal or too loyal. Sometimes people could be so loyal that their distracted and can't see that people can take advantage. If you are really loyal and someone does something thats not right you won't want to do anything about it because it might make you feel like your being disloyal. 

All things considered, while loyalty is good it has a bad side. However, its not what loyalty is but what you make it so you can choose how you want it to effect you, whether its positive or negative.