They challenge my age, the operation - by an old man - of this huge BB-flat tuba, the required brisk movement of these large rotary valves, and all that jazz...sure: in addition to constantly reminding me that I'm SUPPOSED to be making MUSIC.
Check out this really superb cellist (particularly playing the FIRST of the pair of Gavottes - the one in duple meter).
One thing I need to do is to lose the caffeine

The OTHER thing that I need to do (...how many of you are old guitar players, and learn tuba music the same way?) is to learn all the CHORDS to first Gavotte - as they pass so very quickly (mostly: a new chord for every half beat - ie. pair of eighth notes).
I like it.

The second gavotte (triple meter) is much easier. The "notes" are faster, but the CHORDS move MUCH more slowly and are much more obvious - even though there are very few double/triple stops.
As should seem obvious, I'm hitting movements which I previously (over the last fifty-something years of playing) tended to skip past.