I've noticed this happening with a few friends:
They love shopping at Tesco.
They try Aldi/Lidl and think its horrendous.
But then they get to the check out and its WAY cheaper.
But its just not worth it because it was such an AWFUL experience!
They complain a lot that week, especially about how rushed they felt at the checkout, and say 'never again'
Then they go back to Tesco and breath a sigh of relief, but this week, when they get to the till, there's a bit of anxiety, and it feels even more expensive than usual. Is it worth it? (doubt has set in)
They experience a mild hangover guilty feeling in the carpark.
So they try Lidl/Aldi again the following week.
They try to keep positive but are still not enjoying the experience.
Then they get to the till and its so much cheaper, so it was worth it. (Maybe they have toughened up a bit too)
A few weeks later they go back to Tesco.
They enjoy the shopping so much, its like drinking full fat milk after suffering Skimmed milk for weeks.
Its heaven, they stroll around the aisles enjoying themselves and saluting old friends.
Then they head to the till and get an almighty sting with a huge bill.
The gaps between going back to Tesco get bigger.
Eventually they only go to Tesco for the spices / weird things that Lidl and Aldi don't have.
They look back on the days of weekly Tesco shopping much like looking back on wild teenage years, 'weren't we so carefree then, it was like there was no tomorrow'.
The more people that go to Lidl and Aldi, the better they get.
Its a love story really.