The ones that cost people money.
SELF-REFERRAL
Ordering through your own link. Excluded everywhere, and grounds for removal.
A BROKEN OR TRUNCATED LINK
Copying the link incorrectly, or a content editor mangling it. Test it in a private window periodically.
PLACING LINKS WHERE NOBODY NEEDS HOSTING
Traffic without relevance produces nothing.
SPAMMING
Comment spam, forum spam, unsolicited email. Breaches the terms, converts terribly, and damages your reputation.
OVERCLAIMING
Promising performance nobody can guarantee. Produces refunds, which reverse your commission anyway.
NOT DISCLOSING
Legally risky in many places, and damaging when discovered.
EXPECTING QUICK RESULTS
Affiliate income from content takes months to build. Most people quit before their content ranks.
IGNORING THE TERMS
Assuming renewals pay, or that a method is allowed, without checking.
CHECKING STATISTICS DAILY
Produces anxiety and no insight. Write another article instead.