Koehler and Mishra (2008) say:

[…] wicked problems, in contrast to tame problems (such as those in mathematics, chess etc.) have incomplete, changing and contradictory requirements. Solutions to wicked problems are often difficult to realize (or maybe even recognize) because of complex interdependencies among a large number of contextually bound variables. Wicked problems, they argue, cannot be solved in a traditional linear fashion because the problem definition itself evolves as new solutions are considered and/or implemented. Rittel and Weber stated that while attempting to solve a wicked problem, the solution of one of its aspects may reveal or create another even more complex problem. Moreover-wicked problems have no stopping rule and solutions to wicked problem are not “right” or “wrong”, they’re simply “better”, “worse”, “good enough” or “not good enough”. Most importantly, every wicked problem is essentially unique and novel. There are so many factors and conditions — all dynamic — that no two wicked problems are alike. Accordingly, solutions to wicked problems will always be custom designed. For this reason, there is no definitive solution to a technology integration problem. Each issue raised by technology integration presents an ever-evolving set of issues and constraints. (pp. 10-11)

References:
Koehler, M. J., & Mishra, P. (2008). Introducing TPCK. In AACTE Committee on Innovation and Technology (Ed.),Handbook of Technological Pedagogical Content Knowledge (TPCK) (pp. 3–29). New York: Routledge.