What usually causes tooth sensitivity?

Tooth sensitivity can happen for a lot of reasons, including:

• worn enamel
• gum recession
• grinding or clenching
• a cracked tooth
• tooth decay
• sensitivity after whitening
• recent dental treatment

Sometimes it is mild and occasional, and other times it is a sign that something needs attention.

Do you get sensitivity to cold, sweets or brushing? What ended up causing it for you?