Funny enough, there were not a lot of crashes before UK joined EEC due to your given example.
I think that we now have a problem of definition of terms.
Though I'm an Englishman, I have spent almost all my adult life living abroad and have called France my home since the mid-70s and frankly I'm a foreigner here in my current abode in sunny South London. The rest of my family is as disparate and dispersed and I have relatives from France,Sweden, Germany, Austria ...and English ones living all over Europe - and farther afield.
I remember decimalisation and the gradual removal of the conditions that engendered "car crashes" on a daily basis in all areas,: trade, transport, travel, tax, education, healthcare etc etc. The complaints that are beginning to be voiced by people trying to do business with the EU are (imo) an unwelcome surprise but I remember clearly that those conditions were normal. Doing business was a fight and getting almost anything done cross-border required a plan. Ordinary civilians needed to make absolutely sure that they got their ducks in a row.
Over the years, the unutterable shite mountains of red-tape for almost anything in Europe have gradually reduced and generally speaking (from the point of view of an ordinary citizen and ex-businessman) life has become progressively simpler. This is not only from a UK perspective but the European thing more generally.
There are many things wrong with the EU and I agree that it was definitely too much too soon. The EEC otoh made much more sense as it still allowed the people of Europe to feel like Europeans which they most certainly didn't after the war. As the UK didn't get to share in the largesse of those large numbers of German tourists during the 1940s (apart from the Channel Islands) there was never quite the same sense of being a potential battlefield. Now that the oldsters who lived through that (and were the architects of the EU) are pushing up daisies there is no longer a feeling of urgency to get to Winston's United States of Europe ideal and an organic harmonisation of cultures, economies and societies appears a more measured and reasonable approach.
My principal objection to leaving the EU is that having clamoured to be let in, it seemed sensible to continue to have a seat at the negotiating table rather than just being negotiated about. The idea that the UK was never able to influence matters and that it's voice was not heard is fiction. What is quite true is that nobody in the EU is deliriously happy and everybody thinks that their own issues are the most important. It is clumsy and and inefficient and lots of things don't yet work well or at least as they were supposed to.
As an example, I agree entirely that the single currency was and is a huge mistake when it comes to aligning the economies of the member states. When the Euro was introduced we (in Frogworld anyway) were sold the idea that it would replace the USD for international trade and travel so you wouldn't have to juggle invoices and book rates for business nor carry around half a dozen different currencies just for a fortnight's jaunt somewhere. That it was actually going to replace
national currencies was a shock to most people - certainly in France and Germany.
Anyway, whilst I do get the desire to be completely independent and isolate oneself from a perceived alien culture and foreign grouping, this insular approach means perforce that some of the good stuff gets removed with the bad. The things that are in doubt are exactly what and how much; when those become clearer then it will be possible to make some kind of reasoned judgment as whether it was a "good" or a "bad" move. For me personally - as someone who over a few decades had got used to an increasingly easier "european" life, this is already "bad" and will get worse still over the decade or so that represents (optimistically) the rest of my life, so much so that I have decided to go for exclusive French residence and quite possibly citizenship as well. There is a certain irony that the idea of "freedom" that's being promoted is actually a diminishment of freedom for anyone who considers themselves to belong to a larger grouping, like myself.
So here we are, Day 16 - we need considerably more distance to be able to get a general perspective when the new deal affects people (for good or bad!) more widely.
BTW: As this is the "Trump presidency and the consequences" thread, relevance is easily established. It's all
his fault! The fish, the queues, the movement and security fiascos = Trump. Extra costs for trade = Trump again!!!
As always I wish you well