My frustration came when searching for some items on target.com. This screenshot isn't the item I was looking for, but it shows a product page on their website.
What gets me every time I try to shop online from their store is figuring out whether or not something is orderable. You'd think this would be clear. But time and time again, I've been confused as to whether an item can be shipped or not, or picked up in a local store or not. Their buttons are unclear, and there are extra steps to figure out if something will ship to me at my zip code - or not. The above item says it's not available at all, but it was still in their list of water bottles without notice of this until reaching the actual product page - all that does is frustrate me.
Here's a screenshot of a product at walmart.com.
They have the same kind of setup as Target, but theirs always seem to be much clearer as far as what I can order online, or what I have to go pick up instead. Sometimes I'm frustrated when an item can't be shipped, but I have not had nearly the same trouble understanding what can or can't be done, as I have with Target.
Target's website needs different prompts or notices to help customers understand exactly what possibilities (or constraints) there are. In my opinion, Walmart has done a better job with their online store.