My experience with passion fruit is that they tend to shove it in every single mixed fruit juice, and what it does, is give those juices just a bitter aftertaste.
If you've only ever had the good awful underripe honeydew they put in fruit trays for catering, then yeah you'd probably think it's underwhelming. A good, ripe honeydew is my second favorite melon.
Have you ever eaten a passionfruit? You gotta get your fingers in there to get the juices flowing, then you gotta slurp it up with your tongue, licking it clean .. passionfruit surpasses it's name.
Grapefruit grows bunched up, kinda but not really like grapes.
Passionfruit is named for its flower, which has structures that correspond numerically to the stations of the cross and are thus a reference to the Passion of Christ. In this sense, "Passion" refers to suffering, not love or joy.