People who are saying "Guitar" or "Piano" don't play insturments.

The cello:

1. You're literally sitting when you play, whereas many violinists, violists, and bass players have to stand. 2. Big enough strings to not cause a player to develop callouses, no pain/bleeding. 3. Almost always only play one string at a time - no knowledge needed of chords. 4. Until you get ultra good, you will only need to learn 1 clef, and only a handful of key signatures

I think guitar and piano are among the harder of instruments to learn. Bowed string instruments are among the easiest.

Piano or guitar are probably the best instruments for fastest path to gratification i.e. you can play something vaguely nice sounding pretty quickly, on the other of a couple months.

With string instruments you sound like a crying baboon for 2 years, and with brass instruments you sound like an underwater crow for 2 years.

I could recommend taiko (Japanese) drums as an adult hobby. You very quickly get off the ground in terms of making wonderful music together with a group.

Tin whistle could be worth looking at. You'll still need a good ear and a lot of practice for your intonation though.

sorry, in fact i think its hard to play any instrument, but my experience is with piano only. i studied hard for 18 months in my mid 30s and could play many pieces of Erik Satie and some other musicians.