Weather radar
In my case I spent 6 years watching the captain use echo (Marconi?) Radar before an aircraft change allowed me to play with the next set up. It wasn't easy and whilst the books described the criteria and cut offs there is also the varying amount of water droplets not only depending on altitude but the updraft velocities.
My next shared set was on the DC9 with one of the world's best operators and training systems of the time. Led by fast jet pilots of various nationalities in an environment that mixed soft centered returns with cumulus granite..
Followed by the death cruiser, another set and the ITCZ which always had a full crew in the cockpit and occasionally the second captain. I thought I had it sussed until one night heading back to Europe from west Africa, after I had diverted 300nm off track to avoid I realised that we were the only one on vhf2 that was diverting and I had misread the returns.
The radar on the fokker 100 was easier.
As an anecdote a BA colleague during training on the VC10 started avoiding a rocket cloud visually..the skipper took over and flew through it..result heavy turbulence check..broken back and a fleet of ambulances waiting on the tarmac at Colombo. It wasn't showing on radar because radar doesn't (or maybe didnt)show velocities nor shear layers.
Having spent 50 years flying and the last 25 gliding and paragliding around the world I am still learning the vagaries of weather..mostly without personal damage.