In a couple of TV dramas recently, I've noticed that when the characters drink beer at home, they drink out of bottles. While I know some people do this in real life, I don't see it that frequently. This may be partly attributable to the kind of pubs I tend to drink in, but I do also go into local micropubs that offer a good choice of bottles in addition to draught beer and I've noticed that most bottled beer drinkers will opt for a glass. This may be because they are drinking a premium product and want to enjoy it at its best, while the direct-from-bottle drinkers are more likely to be swigging bog standard foreign beers such as San Miguel.
Drinking out the bottle is a much less satisfying experience than drinking the same bottled beer out of a glass. The beer fizzes up in your mouth and in your stomach, with a consequence that you cannot fully taste the flavour and you become bloated more quickly. It can also develop a huge head in the bottle. I expect that dramas like to depict people drinking out of bottles because it looks more rugged or some such nonsense, but bottles were not designed to be drunk out of. On the few occasions when I drink bottled beer at home, I use a glass and find that guests always do as well.
There is also the question of hygiene. Bottled beers can be stored in insecure premises in breweries, warehouses, pub cellars or supermarket storerooms. These types of areas are not kept clean to a food safety standard and there is the real chance of rats, mice, cockroaches or other vermin crawling over crates, urinating and defecating as they go. Some drinkers then put these bottles straight into their mouths. Unless there is some visible dirt on bottles, they are not normally cleaned, and even when they are, it would be quickly for appearance rather than thoroughly for hygiene.
Still, we mustn't be too harsh on the bottle drinkers: if they poured their beer out and supped it from a glass, they might find they're not actually that keen on the flavour.