Crimes in Washington are classified into two broad groups: misdemeanors and felonies. Traffic offenses like speeding or stop sign violations are called "infractions" and are not considered criminal offenses. A misdemeanor is either a simple misdemeanor or a gross misdemeanor. The maximum penalty for a simple misdemeanor is 90 days in jail and a $1,000 fine. The maximum penalty for a gross misdemeanor is one year in jail and a $5,000 fine.
Felonies are classified as Class A, Class B and Class C. Class C felonies are the lesser felonies (e.g., theft) and Class A the most serious (e.g., murder). Penalties vary widely, but the maximum sentence for a Class A felony is life imprisonment.
The more important difference is that a felony conviction will change your life in significant ways. You will lose your right to vote, to own or possess a firearm, to be on a jury, and to hold public office. You will be excluded from many job opportunities on this basis alone. You do NOT want a felony conviction if it can be avoided and in many cases it will be one of your primary objectives in resolving your case.