When Musa a.s. and Bani Israel crossed the Red Sea, they encountered new territory. So it’s only natural that when Bani Israel saw new sights and experienced new experiences, that they were blown away by them, even to the extent of asking Musa a.s. to make a god for them to worship.
It’s very much like when I came to the US more than a decade ago, almost everything I saw was impressive. “Oh, this looks just like in TV!”
And naturally then, you tend to want to emulate what you find impressive. Ever heard the bit about the Arabic-English exchange? At least that’s what I would call it. Oh you know, the bit where English adopted Arabic words such as chemistry, algebra, sugar whereas Arabic adopted English words as television, radio. The exchange is one-sided in terms of benefit, for it shows that the ‘west’ took what is truly beneficial from the ‘east’, but the ‘east’ took what can be destructive from the ‘west’. In other words, you can say that we have this phenomenon where Muslims from the Muslim countries look up to the west in their not-so-impressive values such as entertainment, and when these Muslims (or even non Muslims, it’s the same thing really-think immigration, identity crisis, holding on to one’s heritage) actually come to the west, they will tend to emulate these western values at the expense of their own values which they now look down upon.
This is the mentality of Bani Israel when they oohed and aahed over the new sights they saw after crossing the Red Sea. And when Samiri made that calf, which actually made a sound, maybe a moo, their response was like how you would today respond to teleporting.
And the people of Moses made, after [his departure], from their ornaments a calf – an image having a lowing sound. Did they not see that it could neither speak to them nor guide them to a way? They took it [for worship], and they were wrongdoers. [Al A’raaf 7:148]