I feel like a Baptist, a Mormon, a Catholic, an Evangelical, and a Methodist should all be able to work in a soup kitchen together. All five of these people come from very different groups. They are never going to agree with each other when it comes to certain doctrines. They don't have to feel comfortable worshiping God in each other's churches. And they probably shouldn't. But when it comes to common ground issues, why not work together? We're not as different from each other as we might think.
For Catholics worship is a particular thing, and don’t consider what happens at Protestant services as worship.
Not that those services aren’t good and beneficial, there’s prayer, hymns and reading from and explaining scripture, but it isn’t worship.
Actual worship has always been in relation to the Altar and Sacrifice, and receiving Jesus Himself in Covenant Communion.
The complete self giving of one to the other.