Graduation means so much to us. Its always good to move on, but sometimes we don't really move on. We hold on. We might shift geographically, but we hang on mentally. 18-till-I-die thinking I guess. We might also want to consider that graduation means nothing to us as an occasion except in our own thinking and enjoyment, it makes a lot of work for many people who aren't even graduating. When do they get to graduate from running graduations? Heaven I suppose.
Speaking of which, heaven is the ultimate graduation ceremony. Again, we do nothing to get there, we don't really even deserve it (as some don't deserve to graduate here on earth). But geographically and mentally, we'll not only have graduated, we'll have arrived!