Tangy, adjective: zesty, sharp, acid, acidic, tart, sour, bitter, piquant, spicy, tasty, pungent.
Unhinged, adjective: deranged, demented, unbalanced, unglued, crazed, mad, insane, disturbed, out of one's mind, out of one's tree; informal crazy, mental, nutso, bonkers, batty, loopy, loco, postal, bananas, touched, batshit.
Vapid, adjective: insipid, uninspired, colorless, uninteresting, feeble, flat, dull, boring, tedious, tired, unexciting, uninspiring, unimaginative, uninvolving, lifeless, tame, vacuous, bland, trite, jejune.
Once a tangy
That was vapid
Now a bitter