Oh, where to start...
In Playing Till it Hurts Boober is in medic mode, and actually brings Red momentarily to heel. I love the scene in which he loses his temper at her.
In Boober's Dream we meet his alter ego, Sidebottom. Sidebottom is Boober's repressed fun side. We see how goofy Boober can be, and how he fights against this tendency within himself, but eventually he accepts it. This theme is continued in Boober's Quiet Day.
In Scared Silly Boober goes around scaring people to test their baloobiuses. Wembley tries to get back at him, and fails. The chemistry between the two is wonderful. A very funny ep.
In Marooned Boober and Red are trapped in a rockslide and face the possibility of their own deaths. Red, helpless for once, gives in to fear, and Boober has to be strong and calm for her. Very poignant and sweet. There's a similar theme in Pebble Pox Blues, in which Boober has to overcome his terror of disease to care for Wembley.
In Blanket of Snow, Blanket of Woe Boober cooks up lots of soup. His role is small, but significant: he happily makes soup to pour on the Trash Heap in an effort to revive her.
For me, Boober's crowning moment came in The River of Life. Everyone is poisoned by the chemical waste in the water. Everyone except Boober, who has a sense of smell sensitive enough to detect the waste (and who also has never been seen to swim). He has to try to save the entire colony from death. He forces himself to go up to the hole to outer space to "beg and grovel" for the lives of his friends. The sight of him kneeling as if in prayer in front of the hole, pleading to an empty room, always brings tears to my eyes. He succeeds in saving them by returning Matt's postcards to appease the Outer Space creatures, which proves their existence to Doc.
So, yes, Boober is a very worthy character. On the surface he may seem like a downer, but he can call on inner strength when it is most needed. Not to mention that he takes pride and pleasure in cooking, laundry, and medicine, three very valuable skills!