If you already drink builder’s tea with milk
Try a good Assam or a Ceylon as a loose leaf first — same territory, more of it, and both are forgiving of a rough approach. Then Keemun, which is softer and cocoa-sweet and shows what a single origin offers over a blend. Dian Hong is the one to try if you want to drop the milk: thick and sweet-potato sweet with almost no astringency.
If you have tried green tea and disliked it
Two likely explanations, and both are fixable. The water was too hot, which produces bitterness no timing will correct. Or you met the marine, savoury side of the category and it was not for you. Hojicha addresses the second directly — it is roasted until it tastes of toasted grain and caramel, with no grassiness at all. Longjing is the other route: pan-fired, chestnut-sweet and clean.
If you want to start where the interest is
Tie Guan Yin. It is immediately likeable, very hard to brew badly, and it is the clearest demonstration of why people bother with loose leaf — the same leaf gives six or more distinctly different infusions. Use far less than looks right, because the pellets expand many times over, and give the first steep twenty seconds to open.
If you drink coffee and want something comparable
Nothing in tea is really comparable, and the honest answer is that the closest match depends on which part of coffee you want. For body and behaviour with milk, Assam. For roasted depth without milk, a rested Wuyi rock tea or a Dong Ding. For something dark, thick and sweet, shou pu-erh. TeaHQ records this as a multi-axis question rather than naming one answer.
What not to start with
Gyokuro, matcha and Dan Cong are all excellent and all bad first purchases — the first two because the brewing is far from ordinary practice and the material is expensive to waste, the third because the margin between superb and undrinkable is a few seconds wide. Aged pu-erh is a poor start for a different reason: the age claims are unverifiable and you have no basis yet for judging what you have been sold.