A lot of times, the vape-shop will use a battery that is not fully charged, or a variable-voltage battery that is set at 3.3V (lowest settings). Another difference is the type of tank they have their juices in... different tank's coil orientation and resistance will taste differently.
An EVOD tank also comes pre-installed with a coil, usually 2.5 Ohm or 2.2 Ohm, but sometimes a low-resistance coil of 1.5 or 1.8 Ohm. The juice will taste differently with different resistance coils. Pre-installed coils are not always the best coil... replacement coils almost always last longer and provide better flavor. If the juice tastes hot or burnt, you should use a higher wattage coil, or turn down the Voltage of your VV battery (if you are using one), or try a replacement coil.
Personally, I prefer 1.5 Ohm coils at 3.7V, but some juices just taste a little better with a 1.8 Ohm or even a 2.0/2.2 Ohm coil.... especially bakery flavors or chocolates.
OhmWrecker is correct... high PG levels will make a harsher throat-hit, but if it tasted good in the shop, it should taste similar at home (in your tank). The only variables should be the type of tank (top or bottom coil, single or dual-coil), resistance of coil, and Voltage applied from your battery.