They laugh because:
1- they have 4 Rings already
2- won Million$$$$$ while playing (winning or losing) they are still millionaries
3- they won't work until next training camp, so they have long more than 6 weeks vacations,,,,,something you can't afford
4- They will retire in 3 years, being millionaries, and young,,,,,,and you studying, with a big chance of unemployment, and if employed, with a basic salary for your profession, working 50+ hours per week, with mortgages, car loans, 15 days vacation, and fat with little time to exercise. Also, they are famous, so they can pursue whatever women they like in any given road trip. Also, you gonna retire when 60 yrs old, and they are retiring in their mid 30's.
Believe me, they can laugh.