Retailers hoping to succeed with AI and personalization should be careful about they use data. Consumers are easily annoyed when it is done badly, according to a study by AI platform Clinch.

For one thing, 41.6% of consumers surveyed said they object to excessive retargeting. Another 46.7% said they dislike it when a product is not easy to find after they have clicked on an ad. And 28% object when a product appears in an ad and it is no longer available.

The study does not address email specifically. But it points to warning signs that should also concern email marketers.

“When the experience is irrelevant, repetitive, and doesn’t ‘learn’ from past user interaction/engagement, consumers take notice,” states Oz Etzioni, CEO of Clinch.

The study also found that videos work. However, 57.5% o consumers are more likely to buy a product after watching a video ad if there is an offer or discount. Videos with an immediate call to action have a greater chance of being watched from beginning to end.

Facebook appears to be the most popular shopping tool, leading in all metrics. It is followed by Instagram, general display ads across the web and YouTube.

“Purchases are happening on all the channels some more, some less — but relevancy ultimately determines effectiveness, ” Etzioni adds.

Clinch worked with SurveyMonkey to survey 550 consumers in the U.S.