If you're a bass player? Get a fretless and play it... No excuse... It takes "some time?" But not too much. Everything is the same, but your fingers become the frets. This gives you the options of quarter notes, half notes, slides, and vibratos that you do not have with a fretted bass. You don't have to have frets? Get a fretless and play it... You can get one reasonably priced, give it a try, and don't give up on it too quickly, you have to be more precise, but if you get it down? It's much more fulfilling, trust me. Sorry, but the shot to the nards should be felt, and should be uncomfortable.
https://www.youtube.com/watch?v=wAg1r6zw7Bg' It has a sound you just can't get with frets? It growls... It's the sound of the string vibrating against the neck of the bass? I play with flatwounds, they are more mellow in that regard. But you can play with roundwounds or more advisably "half wounds?" For a more edgy sound, it just makes for potentially more wear on the neck/"Not a" fretboard. But that would take many years of regular play. Trust me? Get a fretless... Get one? Get one this year, and play that thing... If you learn to play it? And it's not really too hard if you're a bass player, you will thank me. WHAPOW! Right in the balls... You don't want that? Get a fretless.