#5. Too many people using one hotspot.
A Wi-Fi router or Access Point is a true bottleneck. Multiple users will be using the same hotspot. Take a look around and if there are more than 5 people using Wi-Fi, then chances are the connection speeds are going to be limited. These days, each person can have 4 or more Wi-Fi devices on their person at any given time. This includes, smartphones, tablets, laptops, cameras, and video game systems. Divide a single Wi-Fi connection by the number of users, times the number of devices they are currently using to connect and the bandwidth speed of the connection speed keeps getting smaller and smaller. The optimal number of devices on one AP/router should be kept at 15 or less.
#4. Distance.
People often connect to the Wi-Fi but they don't even try to look at where the router or access point is. The farther away you are from it, the worse the connection will be. Let's say you walk into a building whether it be a store or a restaurant of some kind, and you connect to the free Wi-Fi but you are only getting 2 out of 5 bars of signal strength. You automatically say, wow this connection sucks. But did you ever take into account where the Wi-Fi is coming from? Can you see the actual access point?
#3. Noise.
I'm not acutally talking about audible sounds type of noise. Noise in Wi-Fi terms is talking about interference from other radio frequency devices and noise most often comes from other Wi-Fi devices. So you're connected to a specific Wi-Fi network SSID but, when you were connecting to it, did you see the list of all the other Wi-Fi SSID network names in that list? Those ones are most likely interfering with your current connection. How about your neighbor next to you. Are they using their phone as a Wi-Fi hotspot to tether their connections to provide Wi-Fi hotspot for their other devices? Any other Wi-Fi network, other than the one you are trying to connect to is called a Rogue network, and can potentially cause noise and interference.
#2. Battery Life.
How low is the battery on your device? If you are using a mobile device, like a smartphone or tablet or something compact, it usually means, the device is likely optimized for lower voltage to extend battery life and also that their Wi-Fi antenna won't be very strong to begin with. What that also means is that there is far less electricity to power the Wi-Fi antenna. As the battery drains past 50% or more, most devices will go into a power saving mode that will decrease electrical power and may also reduce the effectiveness of it's Wi-Fi. Some devices will turn off Wi-Fi entirely at a certain point.
#1. The age and capability of their device. 2.4 Ghz or 5.0 Ghz.
Can your device detect newer Wi-Fi networks on the 5.0 Ghz band? If your device is less than 4 years old, then the answer is most likely yes. The 5.0 Ghz band, is the optimal way to use Wi-Fi as it will experience far less noise interference, and has a much higher connection speed. If the device can only detect and use the 2.4 Ghz band, then those connections will be much poorer and succeptible to interference almost always, and will have a much lower connection speed.
Conclusion.
People can be very quick to determine that the Wi-Fi sucks, but in reality it actually doesn't suck. All 5 of the things mentioned above need to be taken into account. The Wi-Fi router/Access Point could be the absolutely newest, fastest-speed one on the market, and people will still blame it for bad connections, rather than taking a minute to assess their own device and how it connects.
There are also other things to consider, such as the layers past the Wi-Fi router/AP, like "how fast is the actual internet connection?", and "are there problems on the rest of the wired network?"
