This is the only interstitial popup I’ve ever liked. When visiting a UX company’s website, the contact page presented this:
Why do I like this one? It makes me feel like I am talking directly to the company, and that they care why I am here. This pop-up is not trying to sell me something. It’s not (yet again) asking me sign up for your stupid email list. It is simply asking a question, and I am most likely to answer.