Pasta forms evoke many emotions, from slurpy sweetness to penne's warring factions. Some think they modify the flavour of pasta, but that's debatable
On a recent edition of the Quartz Obsession podcast, senior correspondent Annalisa Merelli, a specialist on pasta, said:
Then there's pastina, a small pasta used in broths and stews
Then there's anything egg-based. So I'd throw tagliatelle, lasagna, tortellini in it—everything you know is prepared with eggs and wheat
Shapes have varied functions. Long spaghetti is useful for some sauces. Short pasta is wonderful for sauces.