Why do Tesco jobs have short shifts? ?

You should be smart enough to figure that out for yourself! Supermarkets & retail stores have peak hours where they need extra staff for a few hours, perhaps weekend work. Customer volumes dictate who is needed when. Lots of people shop on their way home from work, for example, so the supermarket is super-busy for an hour or two, and hardly any customers the rest of the day. These are great part-time jobs for full-time students, and as second jobs for people with full-time jobs. There's no way you can live on supermarket/retail work unless you are senior supervisory or managerial staff & needed full-time. You should recognize employer needs before you apply for such work. Get real!

Insurance affordability according to Barack Obama causes the same thing to happen elsewhere.