I think for a lot of us when we were first coming up in playing bass there was a concert video/movie that really inspired us and pushed us in our playing ability. What was that concert video for you? Mine was Metallica's "Cunning Stunts" video from a 2 day concert they played in Fort Worth, Texas in 1997.
I went to live shows to steal licks so vids were less than desirable because they never showed the bass players hands well enough or long enough for me to steal their talent.
I can take the question in 2 directions: The first concert video I had was Metallica's Live Sh*t: Binge & Purge box set. They always put on an energetic show. The first live concert I watched was in support of Metallica's black album. Influential videos: I owned 2 instructional videos that helped to give me a good start, being Stu Hamm's Slap, Pop & Tap for the Bass and Alexis Sklarevski's Slap Bass Program.
The Kids Are Alright (1979). Must've watched that VHS tape a hundred times in the '80s. I was mostly a drummer at the time so Keith Moon's antics were my model! But I did absorb some Entwhistle at the same time. Let's Spend the Night Together (1982) was another well-worn VHS tape in my collection.
U2's Rattle & Hum! I forget which tune it is now, one of the Black & White live numbers, but the Edge and Larry start it up, there's moody lighting, you see Adam in the shadows go to start playing, stops, realizes he's not turned up, turns up his volume knob, waits for the part to cycle around again, enters on the downbeat. It's super subtle, but just a good reminder that stuff happens, remain calm. If you blow your cue, act intentional and come in strong the next time around, it'll be OK.
Pat 'Dirty' Dougherty of Black Oak Arkansas was my first WOW moment guy in '69ish with his big Gibson SG and a coon tail hanging off of it during their sound check which the band privied me and my cousin to after seeing our heads pop up from the Golden West Ballroom's alley dumpster they pulled up next to in 2 limos. we watched in awe as the limo doors opened and an atomic explosion of wild hair and blue denim exited until someone hollered ''look, they even throw their kids away in LA!'' lol after jumping out and telling them how we got rich off the things we'd find thrown out they wanted to look too but there was business to attend. we were so enthralled with them that they let us watch the load in and set up then gave us 2 pairs of tix for the nite's show for clapping at the songs and staying out of the way. the band and crew were the coolest ever and true salt of the Earth even when massive fame hit, they actually remembered me at subsequent shows in LA and invited me to hang out. from then on I wanted to be 'Dirty' but their female entourage was a bit umm distracting from that early goal.
While I had seen plenty of bands on television, most of the time the music was simplistic pop stuff(not necessarily bad, mind you, but nothing all that astounding or challenging), with the bass players just kinda standing in the back, sedate, playing root, I/V, or set riff sort of things. Then, two years after the event, the Monterey Pop movie hit the theaters, and it was a revelation. Live, in concert(no lip synching/playing to backing tracks)performances, the real deal. The segment that stood out for me was this... Even though it's just a few brief snippets, it was the the first time I saw a bassist being enthusiastic, showing joy, moving around, being as important and attention worthy as any other band member(due to my age, I had missed the whole 'Beatles on Sullivan' thing). Plus, it the first time I got to see some breakneck walking, which just mystified me at the time(I had been playing for only a few months). Granted, there were some other great bass moments, Entwistle grinding away while all hell was breaking loose around him, Duck Dunn(with Otis Redding)getting into it, Noel Redding giving Hendrix solid support, Harvey Brooks with The Electric Flag almost matching Larry Taylor's performance, but somehow, "The Mole" left the biggest impression, and decades later I had the chance to thank him personally for it.
Formative event: Watching Steve Swallow play a solo version of Bob Dylan's "I Want You." I knew I was never gonna play like that, but that I was definitely gonna play. Turns out there is a video, not the concert I saw, but from around the same time.