As retailers ponder how to optimize their brick-and-mortar assets, a new study adds further evidence of shoppers' conflicting emotions about the entire experience of in-store shopping.

The study, by payments platform Adyen, identified three key criticisms consumers make about in-store shopping:

First, they don't like lines.  More than three-quarters said they leave stores because of long lines.

Second, they like to be left alone. About half (49%) said they don't want to be helped by a salesperson.

Third, they don't like the pressure. The same percentage, 49%, said they are not always in buying mode, and they don't feel the need to walk out of the store with a purchase in hand.

The study was based on a February 2017 online survey of more than 2,000 US consumers.

The survey results closely align with a slew of recent data signaling American shoppers' evolving preferences, including an increasingly distinct desire to be left to their own devices (literally) while in stores.

An International Council of Shopping Centers (ICSC) survey released in March showed that more than three-fifths of consumers expect that by 2020 they will actually prefer to be left alone to do their own thing while in stores instead of engaging with a sales person.

And in April a survey from Salsify, which provides content management services for digital commerce, found that 77% of shoppers use a mobile device while shopping in-store, whereas just 35% opt to speak to a salesperson if they have a question.

But the ICSC data also pointed up the value of the physical location, noting that nearly three-quarters of shoppers said they’ve made a purchase using their mobile device and picked up the product in store. And more than half said they want to compile a shopping list on a store app and receive a floor map to locate products.

Adyen argued that the responses in its survey underscore the need to provide a unified shopping experience that combines the desired features of on- and off-line shopping. For in-store, that includes the ability to touch and try on goods (cited by 60% of the respondents as a top reason for shopping in-store) and the instant gratification of walking away with a purchase in hand (51%). For online, the top features are line avoidance (64%) and comparison shopping (63%).