The most prominent business process notations in use today are BPMN, EPC and BPEL. While all those languages show similarities on the conceptual level and share similar constructs, the semantics of these constructs and even the intended use of the language itself are often quite different. As a result, users are uncertain when to use which language or construct in a particular language, especially when they have used another business process notation before. Specifically problematic are the semantics of join and loop constructs that have also been heavily discussed in literature. In this paper, we discuss the core characteristics of graph-based and block-structured modeling languages and compare them with respect to their join and loop semantics.